Verb
form a pair or pairs
Source: WordNetThe two old friends paired off Source: Internet
Scene 2: The garden Dorabella and the disguised Guglielmo pair off, as do the other two. Source: Internet
Intuitively, for two sets S and T to have the same cardinality means that it is possible to "pair off" elements of S with elements of T in such a fashion that every element of S is paired off with exactly one element of T and vice versa. Source: Internet