"to make ready for operation," 1957, from initial (adj.) + -ize. The same formation had been used earlier to mean "use initials instead of a name" (1837); "designate by initials" (1833). Related: Initialized; initializing; initialization (1957 in the modern sense).
iniquitous
iniquity
initial
initialese
initialism
initialize
initiand
initiate
initiation
initiative
initiatory