Main Entry: per·sis·tent

Pronunciation: \-tənt\

Function: adjective

Etymology: Latin persistent-, persistens, present participle of persistere

Date: 1826

1 : existing for a long or longer than usual time or continuously: as a : retained beyond the usual period <a persistent leaf> b : continuing without change in function or structure <persistent gills> c : effective in the open for an appreciable time usually through slow volatilizing <mustard gas is persistent> d : degraded only slowly by the environment <persistent pesticides> e : remaining infective for a relatively long time in a vector after an initial period of incubation <persistent viruses>
2 a : continuing or inclined to persist in a course b : continuing to exist despite interference or treatment <a persistent cough> <has been in a persistent vegetative state for two years>

— per·sis·tent·ly adverb