v. i. [ AS. is; akin to G. & Goth. ist, L. est, Gr. &unr_;, Skr. asti. √9. Cf. Am, Entity, Essence, Absent. ] The third person singular of the substantive verb be, in the indicative mood, present tense; as, he is; he is a man. See Be. [ 1913 Webster ]

☞ In some varieties of the Northern dialect of Old English, is was used for all persons of the singular. [ 1913 Webster ]

For thy is I come, and eke Alain. Chaucer. [ 1913 Webster ]

Aye is thou merry. Chaucer. [ 1913 Webster ]

☞ The idiom of using the present for future events sure to happen is a relic of Old English in which the present and future had the same form; as, this year Christmas is on Friday. [ 1913 Webster ]

To-morrow is the new moon. 1 Sam. xx. 5.

See Iso-. [ 1913 Webster ]

{ } [ Gr. 'i`sos equal. ] A prefix or combining form, indicating identity, or equality; the same numerical value; as in isopod, isomorphous, isochromatic. Specif.: (a) (Chem.) Applied to certain compounds having the same composition but different properties; as in isocyanic. (b) (Organic Chem.) Applied to compounds of certain isomeric series in whose structure one carbon atom, at least, is connected with three other carbon atoms; -- contrasted with neo- and normal; as in isoparaffine; isopentane. [ 1913 Webster ]

{ n., } [ F. isabelle. ] See Isabella.

{ n., . [ Said to be named from the Spanish princess Isabella, daughter of king Philip II., in allusion to the color assumed by her shift, which she wore without change from 1601 to 1604, in consequence of a vow made by her. ] A brownish yellow color. [ 1913 Webster ]

(Bot.) A favorite sweet American grape of a purple color. See Fox grape, under Fox. [ 1913 Webster ]

(Zool.) A common American moth (Pyrrharctia isabella), of an isabella color. The larva, called woolly bear and hedgehog caterpillar, is densely covered with hairs, which are black at each end of the body, and red in the middle part. [ 1913 Webster ]

a. Of an isabel or isabella color. [ 1913 Webster ]

a. [ Is- + Gr. a`gelos information. ] Containing the same information; as, isagelous sentences. “The coded message and the original, though appearing entirely unlike, are completely isagelous.” Bacon “The complementary strands have isagelous sequences.” J. D. Watson. -- n. One of two or more objects containing the same information. [ 1913 Webster ]

n. [ L., fr. Fr. &unr_;, fr. &unr_; to introduce; &unr_; into + &unr_; to lead. ] An introduction. [ Obs. ] Harris.