Length  n. 1 measurement or extent from end to end. 2 extent in or of time. 3 distance a thing extends. 4 length of a horse, boat, etc., as a measure of the lead in a race. 5 long stretch or extent. 6 degree of thoroughness in action (went to great lengths). 7 piece of a certain length (length of cloth). 8 prosody quantity of a vowel or syllable. 9 cricket a distance from the batsman at which the ball pitches. B proper amount of this. 10 length of a swimming-pool as a measure of distance swum. at length 1 in detail. 2 after a long time. [old english: related to *long1]