noun
spot advertisement; spot ad
A short commercial message inserted between programs or within a break, as opposed to a longer program-length ad.
この番組の合間にスポット広告が流れる。
Spot ads run during the breaks of this program.
CM is the general term for any commercial message, while スポット広告 specifically refers to short, standalone ads placed between programs.
Compound of スポット (from English 'spot') and 広告 (advertisement).