But Definition

bŭt; bət when unstressed

conjuntion

And on the contrary.

I am old, but you are young.

Webster's New World

And in spite of this; and even so; yet.

He is a villain, but he has some virtues.

Webster's New World

Used to indicate an exception.

No one but she saw the prowler.

American Heritage

That.

I don't question but you're correct.

Webster's New World

With the exception that; except that. Often used with that:

Would have joined the band but he couldn't spare the time; would have resisted but that they lacked courage.

American Heritage

Synonyms:

preposition

With the exception of; excepting; save [nobody came but me]

Webster's New World

Except; other than.

We cannot choose but (to) stay.

Webster's New World

Synonyms:

adverb

Only.

If I had but known.

Webster's New World

Merely; no more than; not otherwise than.

He is but a child.

Webster's New World

Used as an intensive.

Get out of here but fast!

American Heritage

Just.

I heard it but now.

Webster's New World

On the other hand; yet.

Webster's New World

Synonyms:

noun

A concern or objection.

My offer is final, no ifs, ands, or buts.

American Heritage

The outer room, esp. the kitchen, of a cottage.

Webster's New World

An instance or example of using the word "but".

It has to be done – no ifs or buts.

Wiktionary

A limit; a boundary.

Wiktionary

The end; especially the larger or thicker end, or the blunt, in distinction from the sharp, end; the butt.

Wiktionary

prefix

Containing a group of four carbon atoms.

Butyl.

American Heritage

pronoun

Who . . . not; which . . . not.

Not a man but felt it.

Webster's New World

Other Word Forms of But

Noun

Singular:

but

Plural:

buts

Idioms, Phrasal Verbs Related to But

Origin of But

From Middle English but, buten, boute, bouten, from Old English būtan (“out of, outside of, off, round about, except, without, all but, but only, besides, in addition to, in spite of, except that, save, but, only, unless, save that, if only, provided that, outside”), equivalent to be- +‎ out. Cognate with Scots but, bot (“outside, without, but”), West Frisian bûten (“outside of, apart from, other than, except, but”), Dutch buiten (“outside”), German Low German buuten, buute (“outside”), Dutch Low Saxon buten (“outside”). Compare bin, about.

From Wiktionary
Middle English from Old English būtan ud- in Indo-European roots

From American Heritage Dictionary of the English Language, 5th Edition
From butyric

From American Heritage Dictionary of the English Language, 5th Edition