Yesternight
ahd-5
noun.
Last night.
The Century Dictionary and Cyclopedia
On the night last past.
noun.
The night last past.
the GNU version of the Collaborative International Dictionary of English
noun.
The last night; the night last past.
adverb.
On the last night.
Wiktionary, Creative Commons Attribution/Share-Alike License
adverb.
Last night
.