egg1
  
  n.
    - 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. 
- Biology  the female reproductive cell in animals and plants; an ovum.
- informal, dated a person of a specified kind:![]()  he's a thoroughly bad egg. 
- Architecture  a decorative oval moulding, used alternately with triangular figures.
Phrase
  
    - 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.
 
  Derivative
  
  Etymology
  ME (superseding earlier ey, from OE æg): from ON.
 
  
    
egg2
  
  v.
 
(
egg someone on)
 urge or encourage someone to do something foolish or risky.
Etymology
  ME: from ON eggja ‘incite’.