In zoology, monandry refers to female animals who have only one mate. Many bees, butterflies, and humans practice monandry. We just call it getting married.
In most of modern society, monandry is the norm. It's more common to find this scientific-sounding term describing plant and animal reproduction. The habit of certain bees is for the females to stick to monandry, mating only once with just one male. The word monandry comes from the Greek roots mono, "single" or "alone," and aner-, "man."