noun / adjective
holdover
HOHLD-oh-vur/ˈhəʊldəʊvər/
Someone or something that remains from an earlier period.
The brass telephone beside the laptop is a holdover from another era.

Etymology
To hold over is to continue beyond an expected endpoint. The noun first referred to legislators continuing from a previous session, then broadened to any person or thing remaining from an earlier time.
In context
the original bugle call for lights out, the one they were using before taps even existed, was actually a holdover from an existing French bugle call
More examples
- Two holdover members help the new committee get started.
- That rule is a holdover from the company's early days.
- These paper forms are holdovers from before we switched to computers.
Forms
holdover · holdovers