"father," 1680s, from French papa, from Latin papa, originally a reduplicated child's word, similar to Greek pappa (vocative) "o father," pappas "father," pappos "grandfather." The native word is daddy; according to OED the first use of papa was in courtly speech, as a continental affectation, and it was not used by common folk until late 18c.

"father," by 1851, a nursery or provincial abbreviation of dad.

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

c. 1500, colloquial diminutive of dad, with -y (3). Slang daddy-o is attested by 1925 (Eugene O'Neill) but achieved greater popularity in the late 1940s through jazz lyrics.

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]

also granddad, 1793, from grand- + dad. Grand dada attested from 1690s. Grandaddy is attested from 1751; figuratively (in grandaddy of all _____) from 1898.