From the context of tuner with memories, I surmise that this is the mode where the tuner moves from station to station (or preset memory to memory), either stopping for a set time on the station, or stopping until the signal drops out.

On car radios, you have Seek and Scan. The Seek stops at the first strong station, the Scan moves on after 5 or 10 seconds.
In ham radios, you usually can set one or the other.