The German Word ‘Termin’
When we make an ‘appointment‘, we’re usually referring to a business or more formal meeting.
I might have an appointment with my dentist or doctor, or with a client of mine.
A ‘date‘ or ‘rendezvous‘ is used for leisure meetings, such as going out for a meal with a member of the other gender, or to the cinema with your friends.
Of course, you can always quite simple say that you’re meeting some friends after work later.
I hope that helps.