initial

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Of, relating to, or occurring at the beginning; first: took the initial step toward peace.
2. adj. Designating the first letter or letters of a word.
3. n. The first letter of a proper name.
4. n. The first letter of each word of a person's full name considered as a unit: stationery monogrammed with her initials.
5. n. The first letter of a word.
6. n. A large, often highly decorated letter set at the beginning of a chapter, verse, or paragraph.
7. v. To mark or sign with initials, especially for purposes of authorization or approval.

Century Dictionary and Cyclopedia

1. Of or pertaining to the beginning; incipient: as, the initial step in a proceeding.
2. Placed at the beginning; standing at the head: as, the initial letter of a word, or of a chapter in a book.
3. n. The initial or first letter of a word; an initial letter. A person's initials are the first letters in proper order of the words composing his name. To sign a paper with one's initials is to write only the first letter of each of one's names, including the surname. A person's surname being known or separately written, his initials are the first letters of his other names: as, what are Mr. Jones's initials?
4. n. The first letter of a book or writing, or of any division of it, distinguished from the body of the text by larger size or more ornamental character, or both. The initials of medieval manuscript books are often works of high art, elaborate in design and bright in color, generally red. Ornamented and colored initials were also used in many early printed books, sometimes separately executed by hand. In modern books initials, when used, are either plain or ornamental; and they are still sometimes printed in red.
5. n. In plain-song, a tone with which a melody may begin. In strict usage the initials for each mode are prescribed, and called absolute initials.
6. To put one's initial or initials to or on; sign or mark with initials: as, an initialed handkerchief; initialed paper.
7. n. In steam-engines, an abbreviation of initial pressure (which see).

Wiktionary

1. adj. Chronologically first, early; of or pertaining to the beginning, cause or origin
2. adj. Spatially first, placed at the beginning, in the first position; especially said of the first letter of a word
3. n. The first letter of a word or a name.
4. n. In plural, the first letter of each word of a person's full name considered as a unit
5. n. typography, calligraphy A distinguished initial letter of a chapter or section of a document.
6. n. phonology onset, part of a syllable that precedes the syllable nucleus in phonetics and phonology.
7. v. transitive To sign one's initial(s), as an abbreviated signature.

GNU Webster's 1913

1. adj. Of or pertaining to the beginning; marking the commencement; incipient; commencing.
2. adj. Placed at the beginning; standing at the head, as of a list or series.
3. n. The first letter of a word or a name.
4. v. rare To put an initial to; to mark with an initial of initials.

WordNet 3.0

1. adj. occurring at the beginning
2. v. mark with one's initials
3. n. the first letter of a word (especially a person's name)