noun
nine-to-five; regular office hours
Refers to a standard work schedule from 9 a.m. to 5 p.m., often used to describe a typical office job or working hours.
彼は九時五時の仕事に就いた。
He got a nine-to-five job.
九時五時で働くのは久しぶりだ。
It's been a while since I worked nine to five.
定時 means 'regular time' or 'on time' and can refer to fixed working hours, but 九時五時 specifically evokes the 9-to-5 schedule.
Compound of 九時 (nine o'clock) and 五時 (five o'clock), directly representing the typical 9-to-5 work schedule.