(adj) being of crucial importance; ; - Henry Kissinger, Syn. polar, Example:a pivotal event; Its pivotal location has also exposed it to periodic invasions; the polar events of this study; a polar principal
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
a. Of or pertaining to a pivot or turning point; belonging to, or constituting, a pivot; of the nature of a pivot; as, the pivotalopportunity of a career; the pivotal position in a battle. [ 1913 Webster ]