scanning and sweeping

Theoretically is no difference, but practically some radio manufacturers use the terminology scanner when scan for set channels (e.g. 2, 5, 6, 12, …) and sweeper for continuous channel order (e.g. 1, 2, 3, 4, …)

Frequency sweep is output only.
Where as scanner will have a sweeper and try to capture the frequency component of external signal.