Real Dictionary

but
conjunction: You use but to introduce something which contrasts with what you have just said, or to introduce something which adds to what you have just said.

but in American English 1
with the exception of; excepting; save [nobody came but me]
conjunction: on the contrary; yet

but in American English 2
the outer room, esp. the kitchen, of a cottage
noun: the outer or front room of a house; the outer or front apartment in an apartment house

but in American English 3
noun

but in British English 1
contrary to expectation
without it happening or being the case that
preposition: except; save
sentence connector: used to introduce an exclamation

but in British English 2
in or into the outer part (of a house)
noun: the outer room of a two-roomed cottage: usually the kitchen