The Collaborative International Dictionary of English v.0.48:
Yesternight \Yes"ter*night`\, n. The last night; the night last past. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Yesternight \Yes"ter*night`\, adv. [AS. gystran niht. See Yesterday.] On the last night. --B. Jonson. [1913 Webster]