Source : Webster's Revised Unabridged Dictionary (1913)

Y- \Y-\, or I- \I-\ . [OE. y-, i-, AS. ge-, akin to D. & G. ge-,
   OHG. gi-, ga-, Goth. ga-, and perhaps to Latin con-;
   originally meaning, together. Cf. {Com-}, {Aware}, {Enough},
   {Handiwork}, {Ywis}.]
   A prefix of obscure meaning, originally used with verbs,
   adverbs, adjectives, nouns, and pronouns. In the Middle
   English period, it was little employed except with verbs,
   being chiefly used with past participles, though occasionally
   with the infinitive Ycleped, or yclept, is perhaps the only
   word not entirely obsolete which shows this use.

         That no wight mighte it see neither yheere. --Chaucer.

         Neither to ben yburied nor ybrent.       --Chaucer.

   Note: Some examples of Chaucer's use of this prefix are; ibe,
         ibeen, icaught, ycome, ydo, idoon, ygo, iproved,
         ywrought. It inough, enough, it is combined with an
         adjective. Other examples are in the Vocabulary.
         Spenser and later writers frequently employed this
         prefix when affecting an archaic style, and sometimes
         used it incorrectly.