di-

di-¹

a prefix occurring in loanwords from Greek, where it meant "two," "twice," "double" (diphthong); on this model, freely used in the formation of compound words (dicotyledon; dipolar) and in chemical terms (diatomic; disulfide).

Also, dis-². Cf. mono-.

[ME L < Gk, comb. form repr. dís twice, double, akin to dýo TWO. See BI-, TWI-]

di-²

var. of dis-¹ before b, d, l, m, n, r, s, v, and sometimes g and j: digest; divide.

di-³

var. of dia- before a vowel: diorama.

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