English can be tricky, especially when it comes to plural forms. Many learners get confused between “flys” and “flies”. Are both correct? When should you use each?
In this guide, we’ll break it down clearly, give practical examples, and help you avoid common mistakes.
What Does “Flys” Mean? Is It Correct?
The word “flys” is almost always incorrect in standard English when you want the plural of “fly.”
- In formal English, the plural of the insect “fly” is “flies.”
- “Flys” is sometimes seen in brand names, company names, or informal contexts, but it is not grammatically correct in everyday writing or speaking.
Example of incorrect usage:
- ❌ I saw many flys in the kitchen.
Correct version:
- ✅ I saw many flies in the kitchen.
So, if your goal is proper grammar, avoid using “flys” unless it is a specific name.
What Does “Flies” Mean? The Proper Plural Form
“Flies” is the correct plural form of the noun “fly”.
- Used when referring to more than one insect.
- Can also be used as the third-person singular form of the verb “to fly” (e.g., He flies to New York every week).
Examples:
- There are so many flies around the picnic.
- A single fly landed on my sandwich.
- She flies to Paris every summer.
Notice the difference:
- Noun plural: flies (more than one insect)
- Verb third-person singular: flies (he, she, it flies)
Grammar Rules for Using “Fly” in Plural
Here’s a simple rule for ESL learners:
- Most nouns ending in “y” preceded by a consonant change y → ies in plural.
- Example: fly → flies, baby → babies, city → cities
- Example: fly → flies, baby → babies, city → cities
- Nouns ending in “y” preceded by a vowel just add “s.”
- Example: boy → boys, day → days
- Example: boy → boys, day → days
Verb rule:
- For regular verbs ending in “y” preceded by a consonant, y → ies for third-person singular:
- fly → he/she/it flies
- fly → he/she/it flies
Quick table for clarity:
| Word | Singular | Plural (noun) | Third-person singular (verb) |
| Fly | fly | flies | flies |
| Baby | baby | babies | — |
| City | city | cities | — |
| Play | play | plays | plays |
Common Mistakes ESL Learners Make
Many ESL learners confuse flys and flies because:
- They assume “s” always makes plural, ignoring the y → ies rule.
- They don’t distinguish between noun plural and verb third-person singular.
- Informal or spoken English sometimes drops rules, which can cause confusion.
Common mistakes:
- ❌ I hate when flys bother me. → Correct: I hate when flies bother me.
- ❌ He flys to London yesterday. → Correct: He flew to London yesterday.
- ❌ The city have many flys. → Correct: The city has many flies.
Tip: Always ask, “Is this a noun plural or a verb?” That solves most confusion.
Examples: Correct vs. Incorrect Sentences
Here’s a quick comparison of correct vs incorrect usage for clarity:
Plural noun (more than one insect)
- ❌ I killed three flys in the kitchen.
- ✅ I killed three flies in the kitchen.
Third-person singular verb
- ❌ He flys very high in the sky.
- ✅ He flies very high in the sky.
Incorrect informal usage
- ❌ Flys are annoying. → While sometimes seen in texting, it’s not standard.
- ✅ Flies are annoying.
By reading and practicing these examples, learners can quickly internalize the correct form.
Usage Types and Sentence Structures
1. Plural Noun (Flies)
- Subject: Flies are everywhere.
- Object: I hate flies in my kitchen.
- Prepositional phrase: The sandwich is covered with flies.
2. Verb (Third-Person Singular)
- Subject + Verb: He flies to school every day.
- Subject + Modal + Verb: She flies whenever she has a business meeting.
- Negative: He doesn’t fly often.
3. Idiomatic Use
- “Time flies” → Time passes quickly
- “Fly off the handle” → To lose your temper suddenly
- “On the fly” → Doing something quickly without planning
Idioms and Expressions Involving “Fly”
English has many expressions with fly, and they’re important for ESL learners:
| Idiom | Meaning | Example |
| Time flies | Time passes quickly | Time flies when you’re having fun. |
| Fly off the handle | Lose temper suddenly | He flew off the handle when he saw the mess. |
| On the fly | Quickly, without preparation | I made a speech on the fly. |
| Fly by night | Unreliable, temporary | That company seems fly by night. |
| Fly in the ointment | Minor problem in a good situation | The delay was a fly in the ointment. |
These idioms help learners expand vocabulary while practicing proper grammar.
Synonyms and Alternative Phrases
Sometimes, using a synonym can avoid repetitive use of “flies”:
| Word/Phrase | Usage | Example |
| Insects | General | There were many insects in the garden. |
| Bugs | Informal | The picnic was ruined by bugs. |
| Winged pests | Formal | The kitchen was full of winged pests. |
| He/she flies | Verb alternative | She travels frequently. |
| Airborne | Descriptive | The bird became airborne. |
Using alternatives improves writing variety and clarity.
Practice Exercises to Test Your Knowledge
Try these exercises to strengthen your understanding:
1. Fill in the blank (plural noun)
- I hate when ______ bother me in summer.
- The picnic was ruined by several ______.
2. Correct the mistakes
- He flys to work every day.
- I saw many flys in the kitchen.
3. Identify usage
Decide whether flies in each sentence is a noun or verb:
- Flies are annoying in the summer.
- She flies to Paris every month.
Answers:
- Flies (noun), flies (noun), flies (verb), flies (noun), flies (noun), flies (verb)
These exercises help learners internalize grammar rules naturally.
Keyword Variations Comparison Table
| Keyword | Correct Usage | Incorrect Usage | Notes |
| Flys | Rarely correct, mostly informal | ❌ Flys are everywhere | Avoid in formal English |
| Flies | ✅ Correct plural noun, ✅ Verb third-person singular | — | Use in standard writing and speaking |
| Fly | ✅ Singular noun, ✅ Base verb | — | Base form only |
| Flying | ✅ Present participle/gerund | — | He is flying to New York |
| Flew | ✅ Past tense | ❌ Flyed | Past tense of “fly” is irregular |
FAQs
Q1: Is “flys” a correct plural form?
A1: No, the correct plural of “fly” is flies. “Flys” is incorrect in standard English.
Q2: When do we use “flies” as a verb?
A2: “Flies” is used for the third-person singular of the verb “to fly.” Example: She flies to London every week.
Q3: What is the rule for nouns ending in “y”?
A3: If a noun ends in y preceded by a consonant, change y → ies for plural. Example: fly → flies.
Q4: Can “flys” ever be correct?
A4: Only in brand names, proper nouns, or informal contexts. In grammar, it’s considered incorrect.
Q5: How can I avoid confusing “flies” as a noun or verb?
A5: Check the sentence subject. If it refers to insects, it’s a plural noun. If it’s a he/she/it subject, it’s a third-person singular verb.
Conclusion
Understanding the difference between flys and flies is essential for correct English usage. Remember:
- Flies is the proper plural of “fly” and also the third-person singular verb.
- Flys is generally incorrect, except in names or special contexts.
- Watch out for common mistakes, practice exercises, and learn idioms to expand your vocabulary.
With these tips, examples, and practice exercises, you can confidently use “flies” correctly in both speaking and writing. Master this small detail, and your English will sound more natural and professional.
Aldous Huxley was a visionary writer and philosopher whose works explored human nature, consciousness, and the future of society. His ideas continue to challenge minds and inspire generations.
