Definition of: persistent

(pər·sis′tənt, -zis′-) adjective
1. Firm and persevering in a course or resolve.
2. Enduring; permanent; continuous.
3. Bot. Not falling away; remaining for a long time or after the neighboring parts have reached maturity, as the calyx or petals in certain flowers.
4. Zool. Retained throughout life, as the gills of fishes and some amphibians. Compare DECIDUOUS. See synonyms under INDEFATIGABLE, INFLEXIBLE, OBSTINATE, PERMANENT. [<L persistens, -entis, ppr. of persistere. See PERSIST.]
—per·sis′tent·ly adverb