n.
1.the state of being split or cleft
2.the breaking of a chemical bond in a molecule resulting in smaller molecules
3.(embryology) the repeated division of a fertilised ovum
4.the line formed by a groove between two parts (especially the separation between a woman's breasts)
5.the act of cleaving or splitting
Idiom of the Day
back up (someone or something) or back (someone or something) up
to support someone or something
The supervisor made a mistake and his manager refused to back him up.