double-header n.

c. 1300, "twice as much or as large," also "repeated, occurring twice," also "of extra weight, thickness, size, or strength; of two layers," from Old French doble (10c.) "double, two-fold; two-faced, deceitful," from Latin duplus "twofold, twice as much," from duo "two" (from PIE root *dwo- "two") + -plus "more" (see -plus).

From early 14c. as "having a twofold character or relation," also "consisting of two in a set together; being a pair, coupled." From mid-14c. as "characterized by duplicity." The earliest recorded use in English is c. 1200, in double-feast "important Church festival."

Double-chinned is from late 14c.; double-jointed, of persons, is by 1828. Military double time (1833) originally was 130 steps per minute; double quick (adj.) "very quick, hurried" (1822) originally was military, "performed at double time."

The photographic double exposure is by 1872. The cinematic double feature is by 1916. Double figures "numbers that must be represented numerically by two figures" is by 1833. Double-vision is by 1714. Double indemnity in insurance is by 1832; double jeopardy is by 1817. The baseball double play is by 1866.

Double trouble "twice the trouble" is by 1520s; in 19c. America it was the name of a characteristic step of a rustic dance or breakdown, derived from slave dancing on plantations. A double-dip (n.) originally was an ice-cream cone made with two scoops (1936); the figurative sense is by 1940. Double bed "bed made to sleep two persons" is by 1779. Double life "a sustaining of two different characters in life" (typically one virtuous or respectable, the other not) is by 1888.

Old English heafod "top of the body," also "upper end of a slope," also "chief person, leader, ruler; capital city," from Proto-Germanic *haubid (source also of Old Saxon hobid, Old Norse hofuð, Old Frisian haved, Middle Dutch hovet, Dutch hoofd, Old High German houbit, German Haupt, Gothic haubiþ "head"), from PIE root *kaput- "head."

Modern spelling is early 15c., representing what was then a long vowel (as in heat) and remained after pronunciation shifted. Of rounded tops of plants from late 14c. Meaning "origin of a river" is mid-14c. Meaning "obverse of a coin" (the side with the portrait) is from 1680s; meaning "foam on a mug of beer" is first attested 1540s; meaning "toilet" is from 1748, based on location of crew toilet in the bow (or head) of a ship.

Synechdochic use for "person" (as in head count) is first attested late 13c.; of cattle, etc., in this sense from 1510s. As a height measure of persons, from c. 1300. Meaning "drug addict" (usually in a compound with the preferred drug as the first element) is from 1911.

To be over (one's) head "beyond one's comprehension" is by 1620s. To give head "perform fellatio" is from 1950s. Phrase heads will roll "people will be punished" (1930) translates Adolf Hitler. Head case "eccentric or insane person" is from 1966. Head game "mental manipulation" attested by 1972.