What is Split The Atom?
1.
Term; Used to describe a person, usually a female, as being likely to put on weight or get fat as she ages or when she gets older in age.
Term was developed as a metaphor relating to the energy 'expansion' that is created when a uranium atom is split which figuratively describes the 'expansion' of a woman's figure.
"That chick is so sexy, but she's going to split the atom when she gets older"
See
