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

prepend
 /pree`pend'/, vt.

    [by analogy with ?append?] To prefix. As with ?append? (but not ?prefix? or
    ?suffix? as a verb), the direct object is always the thing being added and
    not the original word (or character string, or whatever). ?If you prepend a
    semicolon to the line, the translation routine will pass it through
    unaltered.?


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

prepend

    /pree'pend'/ (by analogy with "append") To prefix or
   add to the beginning.

   [Jargon File]

   (1998-04-23)