What does a man wear when an invitation says 'smart cocktail dress'?

[Birdly]

Am clueless about this sort of thing. I think the only smart thing DH owns is his weddings/funerals/interviews suit!

All advice welcome!

suit

but with a nice tie not a businessy striped one

Thanks Mrs B. Can you tell we don't get out much?!

What used to be known as a 'lounge suit' as opposed to black tie (dinner jacket etc)!! Feel v old now.

He could always wear a smart cocktail dress ...

a black or grey suit.