Is it ensure, insure, or assure?
"large nail," mid-14c., perhaps from Old Norse spik "splinter" (related to Old English spicing "large nail"), from Proto-Germanic *spikaz (cf. Middle Dutch spicher, Dutch spijker "nail," Old English spaca, Old High German speihha "spoke"), from PIE root *spei- "sharp point" (cf. Latin spica "ear of corn," spina "thorn, prickle, backbone," and perhaps pinna "pin" (see pin (n.)); Greek spilas "rock, cliff;" Lettish spile "wooden fork;" Lithuanian speigliai "thorns," spitna "tongue of a buckle," Old English spitu "spit").
But based on gender difficulties in the Germanic words, OED casts doubt on this whole derivation and says the English word may be a borrowing of Latin spica (see spike (n.2)), from the same root. Slang meaning "needle" is from 1923. Meaning "pointed stud in athletic shoes" is from 1832. Electrical sense of "pulse of short duration" is from 1935.
"ear of grain," late 14c., from Latin spica "ear of grain," related to spina "thorn" (see spike (n.1)).
1620s, "to fasten with spikes," see spike (n.1). Meaning "To rise in a spike" is from 1958. Military sense (1680s) means "to disable guns by driving a big nail into the touch-hole." Figurative use of this sense is from 1823. Meaning "to lace (a drink) with liquor" is from 1889. Journalism sense of "to kill a story before publication" (1908) is from the metal spindle in which old-time editors filed hard copy of stories after they were set in type, or especially when rejected for publication.
A brief electrical event of 3 to 25 milliseconds that gives the appearance in the electroencephalogram of a rising and falling vertical line.
An elongated indeterminate inflorescence in which the flowers are attached directly to a common stem, rather than borne on individual stalks arising from the stem. The gladiolus produces spikes. The distinctive spikes of grasses such as wheat or barley are known as spikelets. See illustration at inflorescence.
Drunk: a slightly spifflicated gent/ a spifflicated patient entangling himself in a revolving door
[1906+; fr British dialect spifflicate, ''confound, dumbfound, crush,'' of obscure origin, found by 1785]
To defeat a selection mechanism by introducing a (sometimes temporary) device that forces a specific result. The word is used in several industries; telephone engineers refer to spiking a relay by inserting a pin to hold the relay in either the closed or open state, and railroaders refer to spiking a track switch so that it cannot be moved. In programming environments it normally refers to a temporary change, usually for testing purposes (as opposed to a permanent change, which would be called hard-coded).