In the International System of Quantities, length is any quantity with dimension distance. In other contexts, length is a measured dimension of an object. . Length is a measure of one dimension, whereas area is a measure of two dimensions (length squared) and volume is a measure of three dimensions (length cubed). Length definition, the longest extent of anything as measured from end to end: the length of a river. See more. Lengths definition: the extremes or limits of action Meaning, pronunciation, translations and examples. a length of rope. [ C ] a unit used in describing the distance by which a horse or boat wins a race, equal to the measurement from one end of the horse or boat to the other: We won by two lengths. The length of the table is six feet, and its width is three feet. These pins are available in one- and two-inch lengths. The adult animals reach a maximum length of two meters. Your essay should be no more than 250 words in length. the length of a movie. Definition of Lengths in the Idioms Dictionary. Lengths phrase. What does Lengths expression mean? Definitions by the largest Idiom Dictionary. From Middle English lengthe, from Old English lengþu ('longness; length'), from Proto-Germanic *langiþō, equivalent to long + -th. Cognate with Scots lenth, . TTips for tutors. Length and distance. Measuring lengths. Summary comprising definition of length and metric units of measurement. Fullscreen; Word · PDF . Synonyms for length at Thesaurus.com with free online thesaurus, antonyms, and definitions. Find descriptive alternatives for length. go to some/great/any lengths (to do something) meaning, definition, what is go to some/great/any lengths (to do something): to try very hard or to do whatever is .