mid-14c., "something laid, placed or spread (on something else)," from cover (v.). Sense of "something which veils or screens from sight" is from c. 1400. From c. 1500 as "shelter" of any kind, later especially in hunting, "shrubbery, brush, or thickets which conceal game" (1719).
Meaning "binding or wrapper of a book" is from 1590s; that of "envelope or wrapper for a letter" is by 1748. Meaning "recording of a song already recorded by another" is by 1970, short for cover version (1966). Cover-band "band that plays only cover songs" is by 1981. Cover girl is U.S. slang from 1915, shortening of magazine-cover girl (1899).
Cover-charge is attested by 1913. The immediate sense of cover in it appears to be the old one of "plate, knives, forks, spoons, napkin, wine glasses, etc., used at the table by one person," from French couvert, literally "a cover," in the same sense; supposedly they were so called because they were originally brought together in a case.
According to contemporary publications, cover came to include table condiments and bread and butter, and c. 1910 some restaurants began to charge extra for these. ["... a smart New York restauranteur recently made a 'cover charge' of twenty-five cents for bread and butter and ice-water. Others followed." - Edward Hungerford, "The Personality of American Cities," 1913]
In this sense, cover also probably involves the banquet service use of cover for a charge which includes ("covers") everything provided with the food — menu card, flowers, music, etc.
In recent years hotels, particularly those featuring entertainment in their restaurants, have made a so-called cover charge which includes entertainment in addition to the table service. For instance, at some of the larger hotels in New York, where there is dancing, or cabaret, or high-priced soloists, or entertainment of costly nature provided, there is a cover charge, sometimes as high as $1 the seat. [Hotel Monthly, December 1917]
"a child bereaved of one or both parents, generally the latter," c. 1300, from Late Latin orphanus "parentless child" (source of Old French orfeno, orphenin, Italian orfano), from Greek orphanos "orphaned, without parents, fatherless," literally "deprived," from orphos "bereft."
This is from PIE *orbho- "bereft of father," also "deprived of free status," from root *orbh- "to change allegiance, to pass from one status to another" (source also of 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" (see 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., "bereft of parents," said of a child or young dependent person. Figurative use is from late 15c. The Little Orphan Annie U.S. newspaper comic strip created by Harold Gray (1894-1968) debuted in 1924 in the New York "Daily News." Earlier it was the name (as Little Orphant Annie) of the character in James Whitcomb Riley's 1885 poem, originally titled "Elf Child":
LITTLE Orphant Annie's come to our house to stay,
An' wash the cups an' saucers up, an' brush the crumbs away,
An' shoo the chickens off the porch, an' dust the hearth, an' sweep,
An' make the fire, an' bake the bread, an' earn her board-an'-keep;
An' all us other childern, when the supper-things is done,
We set around the kitchen fire an' has the mostest fun
A-list'nin' to the witch-tales 'at Annie tells about,
An' the Gobble-uns 'at gits you
Orphant was an old, corrupt form of orphan, attested from 17c.