office hours

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Typically, from about 8am to 5pm, Monday to Friday; that is, the times when non-24/7 office workers are at their desks.
• noun An pre-arranged time when a person whose occupation frequently takes them away from their office during working hours is available in their office to answer questions or provide assistance without the requirement for an appointment.