but

Concise Oxford English Dictionary © 2008 Oxford University Press:
but1

▶conjunction

• 1 used to introduce a phrase or clause contrasting with what has come before or with what is expected.

• 2 [with neg. or in questions] other than; otherwise than.

• 3 [with neg.] archaic without it being the case that.

▶preposition except; apart from. ▶adverb

• 1 only.

• 2 Austral./NZ & Scottish informal though; however: he was a nice bloke but.

▶noun an objection: no ifs and buts.

– phrases
but for except for.

■ if it were not for.

– origin OE be-ūtan, būtan, būta ‘outside, without, except’ (see by, out).

Concise Oxford English Dictionary © 2008 Oxford University Press:
but2

▶noun Scottish an outer room, especially in a two-roomed cottage.

– phrases
but and ben see ben2.

– origin C18: from but1 in the early sense ‘outside’.