n. & v.
n. 1 a esp. hist. a piece of armour of esp. metal, carried on the arm or in the hand to deflect blows from the head or body. b a thing serving to protect (insurance is a shield against disaster). 2 a thing resembling a shield, esp.: a a trophy in the form of a shield. b a protective plate or screen in machinery etc. c a shieldlike part of an animal, esp. a shell. d a similar part of a plant. e Geol. a large rigid area of the earth's crust, usu. of Precambrian rock, which has been unaffected by later orogenic episodes. f US a policeman's shield-shaped badge. 3 Heraldry a stylized representation of a shield used for displaying a coat of arms etc.
v.tr. protect or screen, esp. from blame or lawful punishment. shield fern 1 any common fern of the genus Polystichum, with shield-shaped indusia. 2 = BUCKLER 2. shieldless adj.
[ OE sc(i)eld f. Gmc: prob. orig. = board, rel. to SCALE(1) ]