Apart (one word) means separated, distant, or different. A part (two words) means a piece, portion, or share of something larger. A single space separates them on the page, but they mean nearly opposite things — one signals division, the other signals belonging.
The fastest test: if the word “of” follows immediately, you almost certainly want a part. If you can substitute “piece” and the sentence holds, use a part. If substituting “piece” breaks it, use apart.
She is a piece of the team. ✔ → She is a part of the team.
They live two pieces from each other. ✗ → They live two miles apart.
The One Error That Trips Most People Up
The most common mistake in this pair is not choosing the wrong one between them — it is writing “apart of” when you mean “a part of.”
“Apart of” is never correct in English. The preposition “apart” takes “from,” not “of.” You would never write “separate of” or “away of” — and “apart of” fails for the same reason. Whenever “of” follows, the form you need is “a part of,” never “apart of.”
I am so happy to be apart of this team. ✗
I am so happy to be a part of this team. ✔
This chapter is apart of the required reading. ✗
This chapter is a part of the required reading. ✔
What Each Form Means
Apart is most commonly an adverb expressing physical separation, emotional distance, or figurative difference. It can also serve as an adjective, and it forms the compound preposition apart from.
As an adverb: The two sisters grew apart after college. He took the engine apart piece by piece.
As an adjective: Keep the puppies apart until they’ve been vaccinated. With the dogs apart, the house was finally calm.
In the fixed phrase apart from, meaning “except for” or “besides”: Apart from the last five minutes, the film was excellent. She has finished everything apart from the cover letter.
A part is a noun phrase: the article “a” plus the noun “part,” meaning a piece, portion, share, or section of a larger whole. It almost always appears with “of” following it.
She wants to be a part of the solution.
He played a part in everything that followed.
Even a small part of the inheritance would make a difference.
“Part of” vs. “A Part of” — When the Article Is Optional
One point most articles miss: the “a” before “part” is often optional. In many sentences, part of and a part of mean exactly the same thing, and the choice between them is a matter of natural flow rather than correctness.
She is a part of the team. ✔
She is part of the team. ✔ (equally correct)
Uncertainty is a part of life. ✔
Uncertainty is part of life. ✔ (more idiomatic)
When an adjective precedes “part,” the article stays: She is a central part of the team reads better than She is central part of the team. Otherwise, dropping the article is usually the more natural choice in casual and everyday writing.
“A Part” as a Theatrical Role
A part has a specific and common use in the arts: an acting role. This is entirely standard and appears in everyday conversation about theater, film, and television.
She landed a part in the new production.
He’s been hoping for a part with more stage time.
The casting director said the part called for someone older.
This is distinct from the “piece of a whole” use, but the grammar is identical: “a” plus the noun “part,” used here to mean a specific, distinct role rather than a share of a larger thing.
The History Behind the Confusion
Apart entered English in the late 14th century from Anglo-Norman a part, itself from the Latin ad partem — meaning “to the side.” The Old French phrase carried the sense of movement away from a center or a whole, toward one side. In English, this gave apart its core meaning of separation.
Part (the standalone noun) traces to the related Latin partem, meaning a portion or division — the accusative of pars.
So the irony is precise: these two forms share the same Latin root, pars/partem, but English pulled them in opposite directions. Apart inherited the “away from” sense of the Latin prefix ad fused with a directional phrase. The noun part retained the sense of belonging to or making up a whole. The space between them is the trace of that divergence.
Three Tests to Settle It
Test 1 — The “of” signal. If the next word is “of,” use a part. A part of the story, a part of the problem, a part of the solution. This rule has exceptions, but it is correct in the vast majority of cases.
Test 2 — The substitution test. Try swapping in “piece” or “one piece.” If the sentence holds, use a part. If it breaks, use apart.
She is a piece of the team. ✔ → a part
They stood two pieces away. ✗ → apart
Test 3 — The “apart from” check. If you mean “except for” or “besides,” the form you want is the fixed phrase apart from, not a part from.
Apart from the weather, the trip was perfect.
A part from the weather, the trip was perfect. ✗ — this is not a phrase.
Common Mistakes and Quick Fixes
Mistake: I don’t feel apart of the group.
Fix: I don’t feel a part of the group. “Apart of” is never correct. If “of” follows, use a part of.
Mistake: They live miles a part.
Fix: They live miles apart. Distance and separation take apart, one word.
Mistake: Apart from the money, she played a big apart in the decision.
Fix: Apart from the money, she played a big part in the decision. The second instance is the noun “part,” not the adverb “apart.”
Mistake: She came a part when she heard the news.
Fix: She came apart when she heard the news. The idiom “come apart” means to fall to pieces emotionally or physically — always one word.
Examples Side by Side
The friends drifted apart after graduation. (adverb — separation over time)
She became a part of their lives anyway. (noun phrase — belonging)
The clock was taken apart and reassembled. (adverb — dismantled)
Each gear is a part of the mechanism. (noun phrase — piece of a whole)
Apart from the opening chapter, the book is exceptional. (compound preposition — except for)
The opening chapter is a part of the story I keep returning to. (noun phrase — included portion)
He plays a part in the new production starting next month. (noun — theatrical role)
He and his co-star worked best when they weren’t apart for too many scenes. (adverb — physically separated)
Words That Use “Apart” in Fixed Phrases
Several common expressions lock “apart” into permanent one-word form. Knowing these prevents the urge to split them:
fall apart — to disintegrate or lose composure
come apart — to break into pieces, literally or emotionally
tell apart — to distinguish between two things
worlds apart — figuratively very different
set apart — to distinguish or designate as special
pull apart — to separate by force
a breed apart — uniquely different from others
None of these can be replaced with a part.
Quick Practice
Choose the correct form.
- She was glad to be [apart / a part] of the planning committee.
- The cities are an hour [apart / a part] by train.
- He couldn’t tell the twins [apart / a part] even after three years.
- [Apart from / A part from] the timeline, the proposal is strong.
- The engine came [apart / a part] during the inspection.
- He landed [apart / a part] in the film she directed last year.
Answers: 1. a part — 2. apart — 3. apart — 4. Apart from — 5. apart — 6. a part (theatrical role)
FAQs
Is “apart of” ever correct?
No. “Apart of” is not a standard phrase in English. The preposition “apart” takes “from,” not “of” — just as “separate” and “away” take “from,” not “of.” Whenever you want to say something is included in or belongs to something else, write “a part of.” The phrase “apart of” is always an error.
What is the quickest test for apart vs. a part?
Check the word that follows. If “of” comes next, use a part of — almost without exception. If you need to express separation, distance, or the meaning “except for,” use apart.
Is “part of” the same as “a part of”?
In most contexts, yes. “She is part of the team” and “She is a part of the team” mean the same thing. The article “a” is optional. It tends to stay when an adjective precedes “part” — “a central part of the team” — and is more often dropped in idiomatic everyday phrases like “part of life” or “part of the problem.”
What does “a part” mean in theater and film?
In the performing arts, “a part” means a specific acting role. “She landed a part in the new production” and “He auditioned for a part in the film” are both standard uses. The grammar is identical to the “piece of a whole” sense — “a” plus the noun “part” — but the meaning is specifically a distinct character or role.
What is “apart from” and how does it differ from “a part from”?
Apart from is a fixed compound preposition meaning “except for” or “besides”: Apart from the cost, I love the plan. It is always written as one run of two words with no article: apart from, never a part from. “A part from” is not a standard English phrase.
Can “apart” be used as an adjective?
Yes. Apart functions as an adjective when it follows a noun and describes its separated state: Keep the dogs apart. With the cats apart, the house was finally quiet. Stand with your feet apart. In this adjective use, it always means separated or divided — never belonging or included.
The Bottom Line
Apart signals separation, distance, or difference. A part signals belonging, inclusion, or a piece of a whole. The most important rule in this pair is not choosing between them — it is remembering that “apart of” is never correct. When “of” follows, use a part of, every time. Use the “piece” substitution, the “of” signal, and the fixed-phrase checklist to settle any remaining doubts, and the space between these two words will stop costing you anything.
Conclusion
The choice comes down to one question: am I describing separation, or am I describing a piece of something whole? Use “apart” for distance and division. Use “a part” for belonging and inclusion. And remember — “apart of” is never the right answer.
