Webster’s Revised Unabridged Dictionary · 1913
Initial
In·i′tial (ĭn·ĭsh′al), a. [L. initialis, from initium a going in, entrance, beginning, fr. inire to go into, to enter, begin; pref. in- in + ire to go: cf. F. initial. See Issue, and cf. Commence.]
1. Of or pertaining to the beginning; marking the commencement; incipient; commencing; as, the initial symptoms of a disease.
2. Placed at the beginning; standing at the head, as of a list or series; as, the initial letters of a name.
In·i′tial, n. The first letter of a word or a name.
In·i′tial, v. t. [imp. & p. p. Initialed; p. pr. & vb. n. Initialing.] To put an initial to; to mark with an initial of initials. [R.]