This confuses even native English speakers because it breaks the normal rule of adding -s to the end of a word.

What’s the Correct Plural ! Passersby, Passerbys, or Passerbyers?

Passersby is the only grammatically correct plural form. Both passerbys and passerbyers are common mistakes that don’t exist in standard English.

When you see multiple people walking past something, they’re passersby. That’s it. Simple as that.

The confusion comes from how we naturally want to add -s to word endings. But compound nouns follow different rules that make English tricky.

The Grammar Rule Behind the Confusion

A passerby means one person who walks past a place or event. It’s someone who happens to be going by at that moment.

The word combines two parts: “passer” (the person doing the action) and “by” (showing direction or movement). Passer is the noun. By is an adverb.

 You always pluralize the noun in a compound word, never the adverb or preposition. Think of it like this—you’re talking about multiple passers, not multiple bys.

We say mothers-in-law, not mother-in-laws. We say attorneys general, not attorney generals.

Common Mistakes ( Why People Write Passerbys or Passerbyers)

Most English plurals end in -s or -es. Cat becomes cats. Box becomes boxes. Our brains are wired to follow this pattern automatically.

That’s exactly why passerbys feels natural. You see the word passerby and your instinct says “just add -s to the end.” It’s what works 95% of the time in English.

Passerbyers appears because some people treat “passer” and “by” as separate ideas. They think if someone passes by, then multiple people are passerbyers. But that’s not how the compound structure works grammatically.

When speaking, nobody notices the difference. But in writing, using passerbys or passerbyers marks you as someone who doesn’t know the rule.

How to Use Passersby Correctly in Sentences

Using passersby in real sentences helps cement the correct form in your mind. 

• News reporting: “Several passersby witnessed the accident and called 911 immediately.”
  
• Urban scenes: “Street performers attract dozens of passersby who stop to watch and take photos.”
  
• Emergency situations: “Passersby helped pull the driver from the burning vehicle before firefighters arrived.”
  
• Business context: “Our storefront display caught the attention of many passersby during lunch hour.”
  
• Narrative writing: “She stood on the corner, watching passersby rush through their busy lives.”
  
• Safety awareness: “Police asked passersby if anyone had seen the suspect leave the building.”

Just remember it’s always passersby when you mean more than one person walking past.

Quick Reference Guide

Here’s everything you need to remember about using these words correctly:

Singular Form:

• One person walking by = passerby
• “A passerby helped the lost child find her mother”
• Never hyphenate in modern usage

Plural Form:

• Multiple people walking by = passersby
• “Passersby stopped to admire the street art”
• Pluralize the noun (passer), not the adverb (by)

Memory Trick: Think of “passers who go by” and you’ll naturally write passersby.

What NOT to Write:

• ❌ passerbys
• ❌ passerbyers
• ❌ passer-bys
• ❌ passers-by (outdated British style)

Related Word Patterns: If you remember these similar compounds, passersby becomes easier:

• Looker-on → lookers-on
• Hanger-on → hangers-on
• Runner-up → runners-up

The noun always gets plural, never the descriptive part that comes after.

FAQ’s

Is passerbys ever correct?

No, passerbys is never correct in standard English. The only accepted plural form is passersby because you pluralize the noun part of the compound word.

What is the possessive form of passerby?

The possessive singular is passerby’s (with apostrophe-s). For plural possessive, write passersby’s. Example: “The passerby’s testimony was crucial” or “The passersby’s reactions were captured on camera.”

Is passersby one word or two?

Passersby is always one word. Never write it as two separate words (passers by) or with a hyphen (passers-by) in contemporary American English.

How do you pronounce passersby?

Pronounce it as PASS-erz-by, with emphasis on the first syllable. The “s” in passers sounds like a “z” because it comes between vowel sounds. Say it like “passers buy” but faster.

Conclusion

passersby is the only correct plural form. Passerbys and passerbyers don’t exist in proper English, no matter how natural they might feel. The rule is straightforward—pluralize the noun (passer), not the adverb (by). You now know the rule that trips up thousands of English speakers every day.