1. To follow a winding or intricate course
2. To wander aimlessly or casually without urgent destination; ramble
3. To wind or turn in a course or passage

ETYM Latin Maeander, orig., a river in Phrygia, proverbial for its many windings, Greek: cf. French méandre.
A curve in a stream.
Loop-shaped curve in a river flowing across flat country. As a river flows, any curve in its course is accentuated by the current. The current is fastest on the outside of the curve where it cuts into the bank; on the curve's inside the current is slow and deposits any transported material. In this way the river changes its course across the flood plain.
A loop in a river's flow may become so accentuated that it becomes cut off from the normal course and forms an oxbow lake. The word comes from the river Menderes in Turkey.