L&S wrote:dĭaeta (zaeta or zēta , Lampr. Heliog. 29 fin.; 30; and in many MSS. in the foll. passages; cf. the letter D), ae, f., = diaita.
I. A mode of living prescribed by a physician, diet: sola diaeta curari, Cael. Aur. Tard. 2, 12, 146 .--Trop.: sed ego diaeta curari incipio, chirurgiae taedet, Cic. Att. 4, 3, 3 .--
II. A dwelling - place, dwelling room, summer-house, etc. (post-Aug.), Plin. Ep. 2, 17, 15; Suet. Claud. 10; Stat. S. 2, 2, 83; Dig. 7, 1, 13; 32, 55, § 3; Orell. Inscr. 4373 et saep.
D , d (n. indecl., sometimes f. sc. littera), the flat dental mute, corresponding in character and sound to the English...
II. As an initial, the letter d, in pure Latin words, suffers only a vowel after it; the single consonantal compound dr being found only in borrowed words, such as drama, Drusus, Druidae, etc., and in the two onomatopees drenso and drindio. Accordingly, the d of the initial dv, from du, was rejected, and the remaining v either retained unaltered (as in viginti for duiginti; cf. triginta) or changed into b (as in bellum, bis, bonus, for duellum, duis, duonus; v. those words and the letter B). So too in and after the 4th century A.D., di before vowels was pronounced like j (cf. Jovis for Djovis, and Janus for Dianus); and hence, as the Greek di (di) passed into dz, i. e. z (as in z a for d ia, and zeta for diaeta), we sometimes find the same name written in two or three ways, as Diabolenus, Jabolenus, Zabolenus; Jadera, Diadora, Zara.