Meaning of DUAL in English

DUAL

■ adjective

1》 consisting of two parts, elements, or aspects.

↘ Grammar denoting an inflection that refers to exactly two people or things.

2》 (often ~ to ) Mathematics related to another theorem or expression by the interchange of terms, such as ‘point’ and ‘line’.

■ noun

1》 Grammar a ~ inflection.

2》 Mathematics a theorem or expression that is ~ to another.

■ verb ( ~s , ~ling , ~led ) Brit. convert (a road) into a ~ carriageway.

Derivatives

~ity noun ( plural ~ities ).

~ize or ~ise verb

~ly adverb

Origin

ME: from L. ~is , from duo 'two'.

Concise Oxford English vocab.      Сжатый оксфордский словарь английского языка.