to come off something by taking a step. she came to the bottom step and stepped off. Ed was afraid to dive in from the side of the pool, so he just stepped off.
to leave something elevated with one's first step. (Of is usually retained before pronouns.) she stepped off the bottom step and walked down the street. Tony stepped off of the bank and waded across the stream.
to measure a distance by counting the paces required to cover it. she stepped the distance off and noted it on her pad. Liz stepped off the number of feet from the window to the opposite wall.