Dual is a see also of duoplural.
As nouns the difference between dual and duoplural
is that dual
is dual while duoplural
is (linguistics|grammar) duoplural number; the grammatical number of a noun marking two or more of something (as in singular or duoplural) some languages that employ the duoplural
are navajo and taos, where the verb shows singular, dual, and plural numbers, but the nouns are marked only as singular or nonsingular (duoplural).
As an adjective duoplural is
(grammar) pertaining to grammatical number (as in singular and plural), referring to two or more of something; nonsingular.