(1):

(n.) The oval or roundish body laid by domestic poultry and other birds, tortoises, etc. It consists of a yolk, usually surrounded by the "white" or albumen, and inclosed in a shell or strong membrane.

(2):

(n.) A simple cell, from the development of which the young of animals are formed; ovum; germ cell.

(3):

(v. t.) To urge on; to instigate; to incite/

(4):

(n.) Anything resembling an egg in form.