The part of the day during which one works: an eight-hour workday. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "workday" in a sentence
"I came home briefly mid-day (which, in my workday is actually early evening) to change my clothes and make Coley a PB&J sandwich before I went back to work & I did sneak out for a bit to watch the tail end of an old Ted Koppel interview with the seemingly coked-up head of the Church of Scientology and a documentary about the Montana Militia vs. the "green nazis.""
"I've gotten so I try to leave it in my office now at least on the weekends and only check every so often after the "workday" is finished, before starting dinner, after dinner and before bed."
"His 9 a.m. to 9 p.m. workday is so packed he's yet to put more than a picture of his two daughters on the wall."