The word 'tour' entered English in the 14th century from the Old French 'tour', meaning 'a turn, a round, a circuit'. This French term derived from the Latin 'tornus', meaning 'lathe, circle, turn', which itself was borrowed from the Greek 'tornos', signifying a tool for drawing a circle or a lathe. The semantic evolution from the concept of a circular motion to a journey is clear: a tour originally implied a circular trip, returning to the starting point. By the late 17th century, it solidified its modern meaning of a journey for pleasure and sightseeing.

The word is a simplex loanword from French. Its core morpheme 'tour' is not productively segmented in modern English.