INITIAL, also initial letter, point.
1. The first LETTER of a WORD, usually capitalized in a proper NAME: the L of London, the G, B, S of George Bernard Shaw. The practice of using initials or POINTS in handwriting and print has encouraged the growth of such ABBREVIATIONS as symbols, formulas, INITIALISMS, and ACRONYMS: for example, a stands, among others, for acre and are (units of land measurement); e.g. stands for LATIN exempli gratia for the sake of an example; BBC for British Broadcasting Corporation; NATO for North Atlantic Treaty Organization.

2. The large ornamental letter at the start of a page or chapter, especially in an illuminated manuscript.

in·i·tial / iˈnishəl/ • adj. existing or occurring at the beginning: our initial impression was favorable. ∎  (of a letter) at the beginning of a word.• n. (usu. initials) the first letter of a name or word, typically a person's name or a word forming part of a phrase: they carved their initials into the tree trunk.• v. (-tialed, -tial·ing; Brit. -tialled, -tial·ling) [tr.] mark or sign (a document) with one's initials, esp. in order to authorize or validate it. ∎  agree to or ratify (a treaty or contract) by signing it.

initial pert. to a or the beginning. XVI. — L. initiālis, f. initium beginning, f. init-, pp. stem of inīre enter upon, begin, f. IN-1 + īre go, rel. to Skr. éti, Gr. eīmi; see -AL1.
So initiate XVII. initiation XV. — L. initiative sb. XVIII. — F. initiatory XVII.

initial A meristem cell that is actively dividing. Each division yields 1 differentiated cell which joins the main body of specialized plant tissue and 1 cell that retains its meristematic (see MERISTEM) qualities and is, therefore, available to be the initial for a further division.

initial One of a group of cells (or, in lower plants, a single cell) that divides to produce the cells of a plant tissue or organ. The cells of the apical meristem, cambium, and cork cambium are initials.