advocate, alpenstock, arm, athletic supporter, back, backbone, backing, bandeau, bearer, bra, brace, bracer, bracket, brassiere, buttress, cane, carrier, cervix, corselet, corset, crook, crutch, fulcrum, girdle, guy, guywire, jock, jockstrap, mainstay, maintainer, mast, neck, prop, reinforce, reinforcement, reinforcer, rest, resting place, rigging, shoulder, shroud, spine, sprit, staff, standing rigging, stave, stay, stays, stick, stiffener, strengthener, support, supporter, sustainer, upholder, walking stick

For further exploring for "foundation garment" in Webster Dictionary Online