egg

Concise Oxford English Dictionary © 2008 Oxford University Press:
egg1

▶noun

• 1 an oval or round object laid by a female bird, reptile, fish, or invertebrate and containing an ovum which if fertilized can develop into a new organism.

  ■ an infertile egg, typically of the domestic hen, used for food.

• 2 Biology the female reproductive cell in animals and plants; an ovum.

• 3 informal, dated a person of a specified kind: he's a thoroughly bad egg.

• 4 Architecture a decorative oval moulding, used alternately with triangular figures.

– phrases
kill the goose that lays the golden eggs destroy a reliable and valuable source of income. [with allusion to one of Aesop's fables.]
with egg on one's face informal appearing foolish or ridiculous.

– derivatives
eggless adjective,
eggy adjective .

– origin ME (superseding earlier ey, from OE ǣg): from ON.

Concise Oxford English Dictionary © 2008 Oxford University Press:
egg2

▶verb (egg someone on) urge or encourage someone to do something foolish or risky.

– origin ME: from ON eggja ‘incite’.