girth UK /ɡɜːθ/US /ɡɝθ/noun 6verb 1forms 3 noun6 •The distance measured around an object; the circumference. •(informal) One's waistline circumference, most often a large one.He's a lusty, jolly fellow, that lives well, at least three yards in the girth. — 1716 •A band passed under the belly of an animal, which holds a saddle or a harness saddle in place. •The part of an animal around which the girth fits. •A small horizontal brace or girder. •The length of the shortest cycle in a graph. verb1 •To bind as if with a girth or band. formsgirthed · girthing · girths