Used as both a noun and an adverbial time expression. It is neutral and common, but can sound a little more written or formal than ゆうべ in casual conversation.
I slept well last night.
There was an earthquake in Tokyo last night.
The road is wet from last night's rain.
There was a fire in the neighborhood last night.
I've had a headache since last night.
I got a phone call around ten o'clock last night.
Last night I watched a movie at a friend's house.