■ noun
1》 informal an extremely easy task.
↘ chiefly N. Amer. a certainty.
2》 chiefly N. Amer. a girth for a Western saddle or pack, used in Mexico and the western US.
■ verb chiefly N. Amer. secure with a belt.
↘fix (a saddle) securely by means of a girth.
Origin
C19: from Sp. ~a 'girth'.