[hel.met] n [MF, dim. of helme helmet, of Gmc origin; akin to OE helm helmet, OHG helan to conceal--more at hell] (15c) 1: a covering or enclosing headpiece of ancient or medieval armor--see armor illustration
2: any of various protective head coverings usu. made of a hard material to resist impact
3: something resembling a helmet -- hel.met.ed adj -- hel.met.like adj