There's just two in a duo. A duo is a group of two, or a pair.
The noun 'duo' is a singular noun, a word for one group of two people or things (a pair).The plural noun is 'duos' a word for two or more groups of two people or things.
A couple, or a twosome. Also a duo, like Batman and Robin were the dynamic duo.
A duo, a pair...
A pair or duo.
The Centrino Duo processor made by the company Intel has two cores. It is implied in the name "Duo" , which can be translated as "two", "double" or "twice".
Swamp People - 2010 Deadly Duo 4-14 was released on: USA: 16 May 2013
couple or pair ...in music a duo
They're not actresses, they're real people.
A duo or duet.
A "duo" or "duet".
Duo shao 多 少