1660s, "of or pertaining to the Daci, an ancient barbarian people, or their land, which was conquered by Trajan in 104 C.E. and made a Roman province, Dacia, corresponding roughly to modern Romania. From Latin Daci, from Greek Dakoi. As a noun from 1776.

polyethylene terephthalate used as a textile fabric, 1951, proprietary name coined by E.I. du Pont de Nemours & Co.; an invented word of no etymology, on the model of nylon, etc.

metrical foot, late 14c., from Latin dactylus, from Greek daktylos, a unit of measure (a finger-breadth), also "a fruit of the date tree, a date," literally "finger" (also "toe"), a word of unknown origin. The metrical use (a long syllable followed by two short ones) is by analogy with the three joints of a finger. In English versification it refers to an accented syllable followed by two unaccented. The "date" sense also sometimes was used in early Modern English.

"constituting or equivalent to a dactyl; composed of dactyls," 1580s, from Latin dactylicus, from Greek daktylikos "pertaining to a dactyl," from daktylos (see dactyl).

"a fingerprint," 1913, from Latinized form of Greek daktylos "finger" (a word of unknown origin) + -gram.

by 1844 as "the science of study of finger-rings," with -graphy + Latinized form of Greek daktylios "a finger ring," from daktylos "finger," which is of unknown origin. From 1884 as "finger-spelling," which earlier had been dactylology (1650s). Related: Dactylographer; dactylographic.

"a father, papa," recorded from c. 1500, but probably much older, from child's speech, nearly universal and probably prehistoric (compare Welsh tad, Irish daid, Lithuanian tėtė, Sanskrit tatah, Czech tata, Latin tata "father," Greek tata, used by youths to their elders). Compare papa.

1920, from French dada "hobbyhorse," child's nonsense word, selected 1916 by Romanian poet Tristan Tzara (1896-1963), leader of the movement, for its resemblance to meaningless babble.

Freedom: DADA DADA DADA, the howl of clashing colors, the intertwining of all contradictions, grotesqueries, trivialities: LIFE. [T. Tzara, "Dada Manifesto," 1918]

Related: Dadaist; Dadaism.

child's word for "father," 1680s; see dad.

c. 1500, colloquial diminutive of dad, with -y (3). Slang daddy-o is attested by 1949, from bop talk.

Daddy-long-legs is from 1814 in Britain as "crane-fly," a slender, long-legged summer fly. In the U.S., it was used by 1865 as the word for a spider-like arachnid with a small round body and very long, slender legs.

A superstition obtains among our cow-boys that if a cow be lost, its whereabouts may be learned by inquiring of the Daddy-Long-legs (Phalangium), which points out the direction of the lost animal with one of its fore legs. [Frank Cowan, "Curious Facts in the History of Insects, Including Spiders and Scorpions," Philadelphia, 1865]