To apply or dedicate (oneself, time, money, etc) to some pursuit, cause, etc. (Dictionary.com).
From L. devotus, p.p. of devovere "dedicate by a vow, sacrifice oneself, promise solemnly," from → de- "down, away" + vovere "to vow," from votum "a promise to a god, solemn pledge, dedication; that which is promised; a wish, desire, prayer," from PIE root *wegwh- "to speak solemnly, vow, preach;" cf. Skt. vaghat- "one who offers a sacrifice;" Gk. eukhe "vow, wish."
Âdaxtan, âdâzidan, on the model of pardâxtan, pardâzidan "to devote, consecrate, to be busily and attentively engaged; to attempt, care about; to employ" (Steingass), with change of prefix par- to â- (→ theoretician).