From The Collaborative International Dictionary of English v.0.48 [gcide]:
Hestern \Hes"tern\, Hesternal \Hes*ter"nal\, a. [L. hesternus;
akin to heri yesterday.]
Pertaining to yesterday. [Obs.] See Yester, a. --Ld.
Lytton.
[1913 Webster]