not as important as other things or people in a particular activity, idea, or situation:
a diplomat who had a peripheral role in the negotiations
Her involvement in the case was peripheral.
The romance is peripheral to the main plot of the movie.
in the outer area of something, or relating to this area:
the city's peripheral suburbs
the peripheral nervous system
your ability to see things to the side of you when you look straight ahead
peripheral equipment can be connected to a computer and used with it