yestern

Perhaps from yester +‎ -en. Compare also Old English ġiestran (“yesterday”).

yestern (not comparable)

1. (archaic, rare) Of or pertaining to yesterday.
   • 1868, John Conington, transl., The Iliad of Homer:

     Argos, I fear, will pay us soon again
     Her yestern debt […]

   • 1970, Trumbull Stickney, Dramatic Verses‎, Ardent Media, →ISBN, page 35:

     For men born of yesterday are yestern

yestern (not comparable)

1. (archaic) Yesterday.
   • 1949, Lionel Trilling, Matthew Arnold‎, Taylor & Francis, →ISBN, page 169:

     "F. Newman's book I saw yestern at our ouse," Arnold writes to Clough. "He seems to have written himself down an hass.

yestern (plural yesterns)

1. (archaic) Yesterday.
   • 1839, Johann Christoph Friedrich von Schiller, “Knight Toggenburg”, in Montagu Montagu, editor, The Song of the Bell, and other Poems‎, Digitized edition, published 2006, page 85:

     Yestern was the day of hail, […]

   • 1840, Amelia Lane, The Fortress: An Historical Tale of the Fifteenth Century‎, Digitized edition, published 2012, page 305:

     Yestern, who was there could compete with me in strength?

   • 1977, Bill Reed, Dogod‎, Digitized edition, published 2009, →ISBN, page 76:

     For this day ought to promise not so much mulch as yesterday or all the other yesterns all back in a row of boredowndom.

   • 2011, Glenn P. Wolfe, Mneme's Place: Book One‎ (fiction), iUniverse, →ISBN, page 22:

     Jestern, was Joyce's yestern.

• sentery, styrene