step off

Short definition from Wiktionary

Verb

1. 1
   To measure by steps or paces; hence, to divide (a space), or to form a series of marks, by successive measurements, as with dividers.
2. 2
   To avoid a conflict; to back down.
3. 3
   Used other than figuratively or idiomatically: see step, off.

Noun

1. 1
   A drop-off, a sudden decrease.
2. 2
   A preparatory gathering before a larger main event.