both

Etymology

From Middle English bothe, boþe, from Old English bā þā (“both the; both those”) and Old Norse báðir, from Proto-Germanic *bai. Cognate with Saterland Frisian bee (“both”), West Frisian beide (“both”), Dutch beide (“both”), German beide (“both”), Swedish både, båda, Danish både, Norwegian både, Icelandic báðir. Replaced Middle English bō, from Old English bā, a form of Old English bēġen.

det

1. Each of the two; one and the other; referring to two individuals or items.
   Both children are such dolls.
   Which one do you need? – I need both of them.
   He will not bear the loss of his rank, because he can bear the loss of his estate; but he will bear both, because he is prepared for both. 1717, Viscount Bolingbroke, Reflexions upon Exile

pron

1. Each of the two, or of the two kinds.
   "Did you want this one or that one?" — "Give me both."
   They were both here.
   Irregular bedtimes may disrupt healthy brain development in young children, according to a study of intelligence and sleeping habits. ¶ Going to bed at a different time each night affected girls more than boys, but both fared worse on mental tasks than children who had a set bedtime, researchers found. 2013-07-19, Ian Sample, “Irregular bedtimes may affect children's brains”, in The Guardian Weekly, volume 189, number 6, page 34

conj

1. Including both of (used with and).
   Both you and I are students.
2. (obsolete) Including all of (used with and).
   […] having much aduantage both in number, valure, and forepreparation […] 1598, Philip Sidney, The countesse of Pembrokes Arcadia, page 211
   […] as he appreciates its beauty and its rich gifts, as he regards it with venerant love, fed by both his intellectual powers, his contemplation, and his meditation. 1892, Richard Congreve, Essays Political, Social, and Religious, volume 2, page 615