◙ adjective 1. [attrib.] consisting of two parts, elements, or aspects • 双的，两的；两体的；二元的 »their dual role at work and home. 他们在家庭和工作中的双重角色。 [Grammar] (in some languages) denoting an inflection that refers to exactly two people or things (as distinct from singular and plural) • [语法] 双数的（一些语言的一种屈折变化，与单复数变化不同） (in an aircraft) using dual controls • （飞机）双重控制的，复式操纵的 »a dual flight. 复式操纵飞行。 2. [常作 dual to] [Mathematics] (of a theorem, expression, etc.) related to another by the interchange of particular pairs of terms, such as ‘point’ and ‘line’ • [数] （定理或表达式等）对偶的 ◙ noun 1. [Grammar] a dual form of a word • [语法] 双数词 [mass noun] the dual number • 双数 2. [Mathematics] a theorem, expression, etc., that is dual to another • [数] 对偶定理，对偶表达式 ◙ (dualled, dualling) 1. [with obj.] [Brit.] convert (a road) into a dual carriageway • [英] 改（道路）为分隔式车行道 »dualling the A1. 将A1号干线改为分隔式车道。
【派生】
♦ dualize verb 1. (也作 -ise) ♦ dually adverb
【语源】
1. late Middle English (as a noun denoting either of the two middle incisor teeth in each jaw): from Latin dualis, from duo 'two'