di.

diameter.

Also, dia.

* * *

di «dee», noun.

a tone of the musical scale between do and re.

╂[variant of do²]

di.,

diameter.

di-¹,

prefix.

1. a) twice; double; twofold, as in dicotyledon. b) two; having two, as in digraph.

2. containing two atoms, radicals, or the like, of the substance specified, as in dioxide. Also, dis- before s.

╂[< Greek dís twice]

di-²,

prefix. the form of dis-² (Cf. ↑dis-) before b, d, l, m, n, r, s, v, and sometimes before g and j, as in direct, digress.

di-³,

prefix. the form of dia- (Cf. ↑dia-) before vowels, as in diorama.

Di (no period),

Chemistry. didymium.

DI (no periods) or D.I.,

1. disability insurance.

2. discomfort index.

3. drill instructor (in the U.S. Marine Corps).