Lewis & Short

3. dĭs, an inseparable particle [Sanscr. dva, two: dvis, twice; Gr. δίς (δϝις); cf.: bis, bini, dubius, duo; also Sanscr. vi- (for dvi-) = dis-], occurs before vowels only in dishiasco; it stands unchanged before

  1. I. c, p, q, t, s, and di; loses its s before b, d, g, l, m, n, r, and v; and becomes dif-before f. So, discedo, dispar, disquiro, distraho, dissolvo; dibalo, dido, digero, dilabor, dimetior, dinumero, dirigo, divello, etc. Before j (i) we have sometimes dī-, as in dijudico, dijungo, and sometimes dis-, as in disjeci, disjungo. Iacio makes disicio or dissicio. In late Lat. disglutino and disgrego occur; while disrumpo occurs in Cic. Lael. 22, 85; cf. dirrumpo, Plaut. Bacch. 3, 3, 37: dirripio in Cic. de Imp. Pomp. 19, 37, in some MSS.; and dimminuo in MSS. of Plautus, v. Neue Formenl. 2, 782 sq.
  2. II. Meaning.
    1. A. Dis, in most cases, answers to our asunder, in pieces, apart, in two, in different directions, implying separation or division, as in: diffindo, diffugio, digero, discedo, discepto, discerno, discerpo, discindo, dido, diffindo, dimitto, dirumpo, divido, and a multitude of others.
    2. B. Less freq. = Engl. un-, reversing or negativing the meaning of the primitive, as in discingo, disconduco, disconvenio, diffido, diffiteor, disjungo, displiceo, dissimulo, dissocio, dissuadeo, and a few others; so, dinumero, to count as separate objects: disputo, to discuss different views or things.
    3. C. In a few words dis- acquires an intensive force, exceedingly, as, differtus, dilaudo, discupio, disperio (utterly), dispudet, dissuavior, distaedet. This is but a development of its original meaning: thus, differtus is properly stuffed out; dilaudo, to scatter praise of, etc.
    4. D. Between, among, through: dinosco, dirigo (or derigo), dijudico, diligo, dilucesco, dispicio, dissereno.