<p><strong>Adjective</strong></p><ul><li>being before all others with respect to time, order, rank, importance, etc.: the first edition; the first vice president.</li><li>Music: highest or chief among several voices or instruments of the same class: first alto; first horn.</li><li>Automotive: low (def 31).</li><li>(often initial capital letter) being a member of the household or an intimate acquaintance of the president of the United States or of the governor of a state: the First Lady; Checkers, the first dog.</li></ul><p><strong>Adverb</strong></p><ul><li>before all others or anything else in time, order, rank, etc.</li><li>before some other thing, event, etc.: If you're going, phone first.</li><li>for the first time: She first visited Atlanta in 1980.</li><li>in preference to something else; rather; sooner: I'd die first.</li><li>in the first place; firstly.</li></ul><p><strong>Noun</strong></p><ul><li>the person or thing that is first in time, order, rank, etc.</li><li>the beginning.</li><li>the first part; first member of a series.</li><li>Music: the voice or instrument that takes the highest or chief part in its class, especially in an orchestra or chorus.</li><li>a leader of a part or group of performers.</li><li>Automotive: low gear; first gear: She shifted into first and drove off.</li><li>the winning position or rank in a race or other competition.</li><li>Baseball: first base (def 1).</li><li>a product or goods of the first or highest quality.</li><li>goods produced according to specifications, without visible flaws.</li><li>British University: first-class honors.</li></ul>