y-

from the GNU version of the Collaborative International Dictionary of English.

• 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.