The Collaborative International Dictionary of English v.0.48:
Crutch \Crutch\ (kr[u^]ch; 224), n.; pl. Crutches (-[e^]z).
[OE. crucche, AS. crycc, cricc; akin to D. kruk, G.
kr["u]cke, Dan. krykke, Sw. krycka, and to E. crook. See
Crook, and cf. Cricket a low stool.]
1. A staff with a crosspiece at the head, to be placed under
the arm or shoulder, to support the lame or infirm in
I'll lean upon one crutch, and fight with the other.
Rhyme is a crutch that lifts the weak alone. --H.
2. A form of pommel for a woman's saddle, consisting of a
forked rest to hold the leg of the rider.
(a) A knee, or piece of knee timber.
(b) A forked stanchion or post; a crotch. See Crotch.