c. 1300, "pile, heap, or group of things," from a Scandinavian source akin to Old Norse stakkr "haystack" (cognate with Danish stak, Swedish stack "heap, stack"), from Proto-Germanic *stakon- "a stake," from PIE *stog- (source also of Old Church Slavonic stogu "heap," Russian stog "haystack," Lithuanian stokas "pillar"), variant of root *steg- (1) "pole, stick" (see stake (n.)). Meaning "set of shelves on which books are set out" is from 1879. Used of the chimneys of factories, locomotives, etc., since 1825. Of computer data from 1960.
early 14c., "to pile up (grain) into a stack," from stack (n.). Meaning "arrange (a deck of cards) unfairly" (in stack the deck) is first recorded 1825. Stack up "compare against" is 1903, from notion of piles of poker chips (1896). Of aircraft waiting to land, from 1941. Related: Stacked; Stacking.
1796, of hay, past-participle adjective from stack (v.). Of women, "well-built physically; curved in a way considered sexually desirable," 1942.
a ghost word printed in the 1934 "Webster's New International Dictionary" and defined as a noun used by physicists and chemists, meaning "density." In sorting out and separating abbreviations from words in preparing the dictionary's second edition, a card marked "D or d" meaning "density" somehow migrated from the "abbreviations" stack to the "words" stack. The "D or d" entry ended up being typeset as a word, dord, and defined as a synonym for density. The mistake was discovered in 1939.
early 15c., "heap or stack of something," usually consisting of an indefinite number of separate objects arranged in a more or less regular conical or pyramidal form, from Old French pile "a heap, a stack," and directly from Latin pila "a pillar," also "stone barrier, pier" (see pillar).
The sense development in Latin would have been from "pier, harbor wall of stones," to "something heaped up." Middle English pile also could mean "pillar supporting something, pier of a bridge" (mid-15c.). In English, the verb in the sense of "to heap (up)" is recorded from c.1400.
Middle English also had a noun pile meaning "castle, tower, stronghold (late 14c.), which persisted in a sense of "large building." OED regards this as a separate word, of doubtful origin, but other sources treat them as the same.
"stack of hay, straw, etc.," especially if regularly built and thatched to keep off rain, Middle English reke, from Old English hreac, from Proto-Germanic *khraukaz (source also of Old Norse hraukr, Frisian reak, Dutch rook "heap"); perhaps related to ridge (n.).
"stack of hay," Old English muga, muwa "a heap (of grain, pease, etc.), swath of corn; crowd of people," earlier muha, from Proto-Germanic *mugon (source also of Old Norse mugr "a heap," mostr "crowd"), of uncertain origin. Meaning "place in a barn where hay or sheaves of grain are stored" is by 1755.
