Definition of the word split on

The expression "split on" originated in the 1950s and is commonly used today, especially in the technological and scientific fields. The term is derived from the technical terminology in nuclear physics, where "split" refers to the process of dividing a heavy nucleus into two lighter nuclei in a nuclear fission reaction. The term "on" in this context refers to the "trigger" or "control mechanism" that causes the split or fission reaction to occur. In nuclear physics, this "trigger" is typically a neutron or radiation. In a broader sense, the expression "split on" has been adopted to describe any process or mechanism that causes the sudden or unexpected division or separation of something. It often implies a sudden or dramatic event, such as a decision or revelation, that leads to a split or division in a situation or a group. Overall, the origin of "split on" in nuclear physics depicts the destructive force of nuclear fission while in common usage it denotes a sudden and dramatic incident that causes a division or separation.