The Collaborative International Dictionary of English v.0.48:

2 \2\ adj.
   Denoting a quantity consisting of one more than one; one plus
   one more; -- representing the number two as an Arabic
   numeral.

   Syn: two, ii
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

2
    adj 1: being one more than one; "he received two messages" [syn:
           two, 2, ii]
    n 1: the cardinal number that is the sum of one and one or a
         numeral representing this number [syn: two, 2, II,
         deuce]

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

2
 infix.

    In translation software written by hackers, infix 2 often represents the
    syllable to with the connotation ?translate to?: as in dvi2ps (DVI to
    PostScript), int2string (integer to string), and texi2roff (Texinfo to [nt]
    roff). Several versions of a joke have floated around the internet in which
    some idiot programmer fixes the Y2K bug by changing all the Y's in
    something to K's, as in Januark, Februark, etc.


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

2

    In names of translation software,
   infix 2 often represents the word "to" with the connotation
   "translate to", as in dvi2ps (DVI to PostScript),
   int2string (integer to string) and texi2roff (Texinfo to
   [nt]roff).

   [Jargon File]

   (1995-01-25)