RhymeZone: daypart definitions

Definitions of daypart:

noun: (television, radio) A part of the day in which a type of radio or television program apropos for that time period is aired.
verb: (television, radio, transitive) To divide the broadcasting day of (a station) into periods airing different types of material.
verb: (television, radio, transitive) To assign (material) to such a period.

(Definitions from Wiktionary)