1.  pairing(n = noun.act) conjugation, coupling, mating, sexual union, union - the act of pairing a male and female for reproductive purposes; "the casual couplings of adolescents"; "the mating of some species occurs only in the spring"
is a kind of sex, sex activity, sexual activity, sexual practice
has particulars: assortative mating, disassortative mating, cross, crossbreeding, crossing, hybridisation, hybridization, hybridizing, interbreeding, inbreeding, service, servicing
Derived form verb pair₅

2.  pairing(n = noun.act) Array - the act of grouping things or people in pairs; Array
is a kind of grouping
has particulars: buddy system, match-up, matchup
Derived form verb pair₁

1.  The act or process of uniting or arranging in pairs or couples. [1913 Webster]

2.  See To pair off, under Pair, v. i. [1913 Webster]