The Collaborative International Dictionary of English v.0.48:
Vantbrace \Vant"brace\ (v[.a]nt"br[=a]s), Vantbrass \Vant"brass\ (v[.a]nt"br[.a]s), n. [F. avant fore + bras arm: cf. F. brassard armor for the arm, brace, forearm. Cf. Vambrace.] (Anc. Armor) Armor for the arm; vambrace. --Milton. [1913 Webster]