The Jargon File (version 4.4.7, 29 Dec 2003):

tayste
 /tayst/

    n. Two bits; also as taste. Syn. crumb, quarter. See nybble.


The Free On-line Dictionary of Computing (30 December 2018):

crumb
quarter
tayste

    (Or tayste /tayst/) Silly suggested term for
   two binary digits.

   The term "quarter" has also been suggested, referring to the
   US 25-cent coin.  This was once equal in value to two of the
   eight "bits" - pie-slice-shaped "pieces of eight" - into which
   Spanish silver crowns were cut to make change.

   [Jargon File]

   (2007-05-31)