Is it ensure, insure, or assure?
c.1300, from Late Latin orphanus "parentless child" (source of Old French orfeno, Italian orfano), from Greek orphanos "orphaned, without parents, fatherless," literally "deprived," from orphos "bereft," from PIE *orbho- "bereft of father," also "deprived of free status," from root *orbh- "to change allegiance, to pass from one status to another" (cf. Hittite harb- "change allegiance," Latin orbus "bereft," Sanskrit arbhah "weak, child," Armenian orb "orphan," Old Irish orbe "heir," Old Church Slavonic rabu "slave," rabota "servitude" (cf. robot), Gothic arbja, German erbe, Old English ierfa "heir," Old High German arabeit, German Arbeit "work," Old Frisian arbed, Old English earfoð "hardship, suffering, trouble"). As an adjective from late 15c.
1814, from orphan (n.). Related: Orphaned; orphaning.
A model of a car, boat, computer, etc, which is no longer being manufactured, and for which spare parts are hard to find (1940s+)