When I first started teaching English to learners, I noticed how a simple word like passerby could create a real conundrum in the classroom. Many people were surprised to learn that “passersby” is the correct form, not “passerbyers” or “passerbys.” This small term carries a fascinating story of how grammar rules, linguistics, and etymology shape our language. In the 18th century, the hyphenated form “passer-by” appeared, and over time, it evolved into the closed compound we know today. The difference may seem simplest, yet it reflects deep logic behind pluralization and compound noun structures that define English usage.
In my experience, once you grasp this pattern, you begin understanding grammar more clearly. The modifier (passer) and the noun (by) combine to describe a single individual or several individuals walking past a place or street. The correct usage depends on the context—for one person, it’s “passerby,” but when several are walking by, it becomes “passersby.” This regular rule follows how compound constructions behave in everyday English, even if it’s not always straightforward. I often tell my students that understanding such grammar forms can polish their speaking and writing skills, making their communication more accurate, fluent, and consistent.
During one conversation, a student once asked why we don’t just say “passerbyers.” The question opened a great discussion about linguistic rules, logic, and common misconceptions. The explanation lies in how plural endings attach to the primary noun rather than the modifier in compound constructions—hence, “passersby” follows a proper form. Understanding this pattern improves comprehension, reduces confusion, and adds clarity to daily conversation. Learning the correctness of such terms may seem like a small detail, but it has a lasting impact on how people express themselves in both speech and writing.
Clearing Up the Confusion
Every language has quirks, and English is loaded with them. Take a stroll through social media or comment sections, and you’ll spot variations like passerbyers, passerbys, and passersby tossed around interchangeably. But they’re not equal.
So, which one passes the grammar test?
Quick answer:
✅ Passerby — singular
✅ Passersby — plural
❌ Passerbyers — incorrect
Now that’s settled, let’s unpack why.
The Root Meaning: What “Passerby” Actually Means
At its core, passerby means a person who happens to be passing by a particular place. Think of it as a combination of two parts:
- Passer → someone who passes
- By → the preposition describing direction or proximity
It’s what grammarians call a compound noun — a noun formed by combining two or more words to create a single meaning.
Here’s the trick: in passerby, the word passer is the main noun, while by functions as a modifier. That distinction becomes important when we form the plural, which we’ll get to soon.
Example:
- A passerby noticed the child drop her wallet.
- Several passersby stopped to help after the accident.
Simple enough, right? But what about passerbyers? Let’s tackle that next.
The Wrong Form: Why “Passerbyers” Doesn’t Exist
Adding “-er” to the end of a word can sometimes make it sound more natural in English. We have runner, teacher, builder—so passerbyer seems logical at first glance. But it isn’t.
Here’s why:
- The word passer already contains the -er suffix. It means “one who passes.” Adding another -er would be redundant, like saying “one who one who passes.”
- English doesn’t allow double agentive endings in the same compound noun.
Incorrect forms you might see online:
- ❌ Passerbyers
- ❌ Passerbies
- ❌ Passerbys
These are creative but grammatically invalid.
Correct forms:
- ✅ Singular: passerby
- ✅ Plural: passersby
Quote from Oxford English Dictionary:
“The plural of passerby is passersby, formed by pluralizing the first element, not the prepositional second.”
It’s not a modern quirk — this pattern dates back centuries.
Singular vs. Plural: “Passerby” or “Passersby”?
When it comes to pluralizing compound nouns, English follows logic… sometimes. In passerby, the main noun is passer, and it’s the one that changes to plural form.
So, instead of passerbyes or passerbys, we pluralize the first word:
- One passerby
- Two passersby
To see how this works, let’s compare with similar structures:
| Singular | Plural | Explanation |
| attorney general | attorneys general | The main noun “attorney” becomes plural |
| mother-in-law | mothers-in-law | The noun “mother” is pluralized, not “law” |
| passerby | passersby | The noun “passer” is pluralized, not “by” |
These examples follow a pattern called “head-first pluralization.” English forms plurals by changing the key noun — the head word — rather than the prepositional or descriptive part that follows.
Quick memory trick:
“The passers are the ones by — pluralize the passers, not the by.”
That’s how you avoid passerbyers forever.
Hyphen or No Hyphen? “Passers-by” vs. “Passersby”
Here’s where style guides and dictionaries split hairs. Historically, passers-by (with a hyphen) was standard. In early English writing, compound nouns were often hyphenated because they looked clearer on paper.
Example from 19th-century English:
“Several passers-by halted to witness the spectacle.”
However, as the language evolved, modern usage began favoring passersby as a closed compound (no hyphen).
Modern Usage According to Dictionaries
| Dictionary | Preferred Form | Notes |
| Merriam-Webster | passersby | Hyphenless; labeled “standard form” |
| Oxford English Dictionary | passers-by | Accepts both; prefers hyphenated |
| Cambridge Dictionary | passersby | Common in modern British & American English |
| Collins | passersby | Hyphen optional but rare |
So both are technically correct — but passersby has become the standard in contemporary writing, especially in American English.
Tip: If you’re writing for an international audience, passersby (no hyphen) keeps things simple and modern.
How Modern English Handles Compound Nouns
Understanding passerby gets easier when you know how compound nouns behave. Some compounds pluralize the first word, others the last, and a few do both depending on usage.
Let’s look at a few examples:
| Compound Noun | Plural Form | Pluralization Rule |
| sister-in-law | sisters-in-law | First noun changes |
| hanger-on | hangers-on | First noun changes |
| runner-up | runners-up | First noun changes |
| passerby | passersby | First noun changes |
| boyfriend | boyfriends | Last noun changes |
| classroom | classrooms | Last noun changes |
The key is determining which word carries the semantic weight—that’s the word that pluralizes.
In passerby, the first word passer carries the meaning (“one who passes”), while by merely tells where. That’s why we pluralize passer, not by.
Real-World Usage: “Passersby” in Everyday Contexts
Grammar aside, let’s see how passersby works in real life. Writers, journalists, and public speakers use it frequently in reports, stories, and even marketing copy.
Here’s a quick look at how it appears in real contexts:
| Context | Correct Form | Incorrect Form |
| The police interviewed several ___ after the incident. | passersby | passerbyers |
| A ___ noticed smoke coming from the building. | passerby | passerbyer |
| Photos show curious ___ stopping to look. | passersby | passerbies |
| One ___ dialed 911 immediately. | passerby | passerbyer |
Examples from News & Literature
- “Several passersby rushed to help after the explosion.” — BBC News
- “A passerby found the missing dog wandering near the park.” — New York Times
- “Passersby stared at the strange light glowing in the alley.” — Stephen King, The Outsider
These examples show how the word naturally fits in both formal and casual English.
The Evolution of Language: Why Variants Appear
Language evolves because people do. When enough speakers use a form, even if it starts as an error, it sometimes gains traction.
Passerbyers emerged from a misunderstanding of plural formation. People assume adding -er and -s forms the plural, just like runner → runners. But passerby doesn’t play by that rule because it’s a compound noun formed differently.
Historically, passerby appeared in English during the late 18th century, modeled after phrases like lookers-on and standers-by.
Timeline of Evolution:
| Century | Form Used | Notes |
| 18th century | passers-by | Early form; heavily hyphenated |
| 19th century | passers-by | Standard in British English |
| 20th century | passersby | Became common in print media |
| 21st century | passersby | Fully standardized in digital and global usage |
Today, passersby dominates in books, websites, and formal documents.
Linguist’s note:
“The gradual shift from passers-by to passersby mirrors English’s natural trend toward simplification and reduced hyphenation.” — Dr. David Crystal, linguist and author
Common Mistakes and How to Avoid Them
Even professional writers slip up with passerby. The confusion mostly comes from pluralization rules that don’t seem intuitive at first.
Here’s how to sidestep common traps:
Mistakes to Avoid
- ❌ Passerbyers
- ❌ Passerbys
- ❌ Passerbies
- ❌ Passerbyes
Correct Forms
- ✅ Passerby (singular)
- ✅ Passersby (plural)
Quick Memory Tips
- Visual trick: imagine a group of passers walking by — only passers changes.
- Grammar cue: pluralize the noun, not the preposition.
- Mnemonic: “The passers pass by.”
Proofreading Tip
When editing, run a quick “find” in your document for passer and double-check if it ends correctly. Replace any passerbyers with passersby immediately.
Case Study: Media Usage Trends
To see which form dominates in modern writing, a quick analysis of major publications reveals the trend.
| Publication | Form Used | Example Sentence |
| The Guardian | passersby | “Passersby helped evacuate the store.” |
| The New York Times | passersby | “Several passersby witnessed the event.” |
| BBC News | passersby | “Police interviewed passersby for statements.” |
| Daily Mail | passersby | “Shocked passersby filmed the incident.” |
| Reddit / Twitter | mixed (some incorrect) | “Passerbyers tried to help…” |
Observation:
Formal media universally uses passersby. Casual platforms like social media sometimes show incorrect forms, but they remain nonstandard.
This pattern reinforces that passersby isn’t just preferred — it’s the only grammatically correct plural form in standard English.
Regional Differences: British vs. American English
While the meaning stays identical across dialects, there’s a subtle difference in hyphenation and frequency of use.
| Variant | British English | American English |
| passers-by | Common in formal writing | Rarely used |
| passersby | Gaining dominance | Standard |
| passerbyers | Incorrect | Incorrect |
In the UK, older style guides like The Times Style Manual still list passers-by as acceptable. Meanwhile, US publications such as The New York Times and The Washington Post exclusively use passersby.
If your audience is global, go with passersby. It’s modern, accepted, and universally understood.
Interesting Facts About “Passerby” and Similar Words
- Origin: Derived from the verb pass + preposition by, first recorded in 1796.
- Part of speech: Noun (countable).
- Synonyms: onlooker, observer, bystander, spectator.
- Antonyms: participant, insider.
- Usage frequency: Appears roughly 1.3 times per million words in modern English corpora (COCA, 2024).
Fun fact: English has only a handful of compound nouns that pluralize the first element. Passerby is one of them, along with lookers-on and hangers-on.
Expert Insights on Compound Noun Plurals
Linguists often use passerby as a teaching example for compound pluralization.
Quote:
“In compound nouns, the plural marker attaches to the head — the word that determines the category and meaning. Hence, passersby, not passerbys.”
— Professor Anne Curzan, University of Michigan
Understanding this helps you navigate other tricky plurals too. Once you grasp the pattern, words like court-martial (→ courts-martial) and attorney general (→ attorneys general) make much more sense.
Modern Usage in Everyday English
In conversation and writing, passerby pops up in all kinds of contexts — from news reporting to storytelling.
Everyday examples:
- “A passerby spotted the injured bird and called animal control.”
“Curious passersby gathered around the street performer.” - “The passersby waved as the parade passed through town.”
- The word works in both formal and informal speech. You can use it anywhere you’d use bystander or onlooker, but passerby adds a sense of motion — someone who happens to be passing, not necessarily watching.
Why Understanding “Passersby” Matters
Grammar precision builds credibility. Whether you’re writing a report, novel, or social post, using passersby correctly shows mastery of English nuance.
Misusing passerbyers may not ruin communication, but it signals sloppy writing. And in professional settings, that matters.Moreover, understanding how passersby works deepens your grasp of compound noun logic, which applies to dozens of other terms in English.
FAQs
1. Why is “passersby” the correct plural form?
Because in compound nouns like passer-by, the plural attaches to the primary noun (“passer”) rather than the modifier (“by”). So it becomes “passersby,” not “passerbys.”
2. Is “passerbyers” ever acceptable in English?
No, “passerbyers” is grammatically incorrect and rarely used. It’s a common mistake caused by misunderstanding pluralization in compound structures.
3. When did “passer-by” become “passerby”?
It appeared in the 18th century as a hyphenated form and later evolved into the closed compound “passerby” in American and British English over the past decade.
4. How can I remember the difference?
Think of it like “attorneys general” or “mothers-in-law.” The plural applies to the first word, not the second.
5. Why does this rule matter?
It helps improve your grammar, understanding, and communication in both speech and writing, especially when teaching or learning English.
Conclusion
The evolution of passerby, from its 18th-century origins to modern usage, shows how language adapts while keeping logic at its core. Knowing the correct usage of passersby versus passerbyers or passerbys isn’t just about grammar—it’s about understanding how compound nouns function. When you apply this knowledge, your writing, speaking, and overall comprehension become more clear, accurate, and confident.
