Back when I used to commute into an office, we had certain "core hours" during the day. Usually, the day started for most people between the hours of 7 and 9am and ended between 3 and 5pm - you can pick a 7-3, 8-4 or 9-5 schedule. Of course, the idea of "only" 8-hours of work each day can seem like a bit of a thing of the past nowadays, unfortunately.
Luckily, I work from home now and completely make up my own hours. Lovely.