<em>Which</em> is a grammatical word: it asks you to choose from a set ("Which platform does the train leave from?") or introduces a clause ("the report, which arrived on Friday"). <em>Witch</em> is a noun naming a person believed to practise magic ("the witch in Hansel and Gretel"). They sound the same in almost every accent but share no meaning, so the only real danger is a typo.
The core difference
These words are pronounced identically by most English speakers, yet they sit in different corners of the language. Which is a function word — it does grammatical work and cannot stand alone as a thing. Witch is an ordinary countable noun: one witch, two witches.
The trap is that both spellings are real words, so no spellchecker will flag you. "Send me the file witch you edited" passes every automatic check and reaches your reader intact.
How to use which
Which has two jobs. It asks a reader to pick from a limited range of options: "Which of the three quotes came in lowest?" And it introduces a relative clause describing a thing or an idea: "The scheme, which had been running since spring, was quietly dropped."
It also appears in a set of fixed phrases that are worth recognising as units:
- in which case — "He may refuse, in which case we start again."
- which is why — "The lift was broken, which is why I was late."
- both of which / all of which / some of which — "Two proposals, both of which need costing."
How to use witch
Witch names a person, so it behaves like any other noun: it takes a or the, it pluralises, and it forms compounds. You will meet it in witchcraft, bewitched, witch-hunt (used figuratively for a campaign against people accused without evidence), and witch hazel, the plant extract sold in chemists.
The test
Try replacing the word with "what one" or "that". If either fits, you want which: "Which one do you prefer?", "the email that arrived late". If instead you could put a, the or every in front of it and you are describing a person, you want witch.
The mistake to watch for
Nearly all errors here are keyboard slips rather than genuine confusion, which means proofreading beats memorising. When you scan a draft, treat every instance of witch as suspicious unless the subject is folklore. A third spelling sometimes appears — wich — and it is not a word in its own right; it survives only inside sandwich and in place names such as Norwich and Nantwich.
Frequently Asked Questions
Is it "which is why" or "witch is why"?
"Which is why." The phrase links back to a reason you have just given — "The server crashed, which is why the site was down" — so it needs the relative word, never the noun.
Why doesn't my spellchecker catch "witch" when I mean "which"?
Because <em>witch</em> is a correctly spelled English word. Basic spellcheckers only compare words against a dictionary; catching this requires a grammar checker that reads context, and even those miss it regularly.
Do which and witch really sound identical?
For the vast majority of speakers, yes. A minority of accents — parts of Scotland, Ireland and the American South — keep an older breathy <em>hw-</em> sound in <em>which</em>, making the pair distinguishable, but this is now uncommon.