This word means "two people." It can also refer to "a couple" or "a pair" of individuals. Like "一人 (ひとり)", it is an irregular but common reading when counting people in Japanese.

「二(ふた)人(り)」を意(い)味(み)し、カップルやペアも指(さ)します。人(にん)数(ずう)を数(かぞ)える際(さい)の特(とく)別(べつ)な読(よ)み方(かた)です。