Firstly: The Definition of Walking (Sa`y)
Linguistically, sa`y means walking or running without exertion.
Secondly: The Definitions of Safa and Marwah
Linguistically, safa means “boulders”, or large, arid, barren rocks. Some hold that it means a smooth boulder.
Technically, Safa is a raised part of the hill of Abu Qubays. From it, sa`y begins. It is at the south end of the walking area.
Linguistically, marwah are white, gleaming rocks. The plural is marw.
Technically, Marwah is a hill in Mecca. Sa`y ends at it. It is a part of the mountain of Qu`ayqi`an, which occurs at the north end of the walking area.
Thirdly: The Definition of Walking between Safa and Marwah
Technically, walking between Safa and Marwah traversing the distance between Safa and Marwah seven times during Hajj or `umrah.