Amplifiers oscillate, and oscillators don't.
I am reminded of a comment in either tthe Art of Electronics
or the Student Manual for same (I forget which edition) where the author
points out that an emitter follower can turn into a very effective RF
oscillator.
[In case you're rondering, it depends on the inductance of the collector
connection causing the thing to be a common emitter amplifier at RF]
-tony