The Collaborative International Dictionary of English v.0.48:

Multangular \Mul*tan"gu*lar\, a. [L. multangulus; multus much,
   many + angulus angle: cf. F. multangulaire.]
   Having many angles. -- Mul*tan"gu*lar*ly, adv. --
   Mul*tan"gu*lar*ness, n.
   [1913 Webster]