Is it ensure, insure, or assure?
1640s, alteration of pompone, pumpion "melon, pumpkin" (1540s), from Middle French pompon, from Latin peponem (nominative pepo) "melon," from Greek pepon "melon," probably originally "cooked (by the sun)," hence "ripe;" from peptein "to cook" (see cook (n.)). Pumpkin-pie is recorded from 1650s. Pumpkin-head, American English colloquial for "person with hair cut short all around" is recorded from 1781. Vulgar American English alternative spelling punkin attested by 1806.
America's a dandy place:
The people are all brothers:
And when one's got a punkin pye,
He shares it with the others.
[from "A Song for the Fourth of July, 1806," in "The Port Folio," Philadelphia, Aug. 30, 1806]
A humourous term for the token - the object (notional or real) that gives its possessor (the "pumpking" or the "pumpkineer") exclusive access to something, e.g. applying patches to a master copy of source (for which the pumpkin is called a "patch pumpkin").
David Croy once told me once that at a previous job, there was one tape drive and multiple systems that used it for backups. But instead of some high-tech exclusion software, they used a low-tech method to prevent multiple simultaneous backups: a stuffed pumpkin. No one was allowed to make backups unless they had the "backup pumpkin".