noun

1. a band put around the belly of a horse or other animal for holding a saddle, pack, etc.
2. the circumference, as of a tree trunk or person's waist

Etymology: ME gerth < ON gjörth < base of gyrtha, to encircle, akin to OE gyrdan: see gird

transitive verb

1. to girdle; encircle
2. to fasten or bind with a girth

intransitive verb