Organ stop and Organ pipe

Organ stop noun - A graduated set of organ pipes of like tone quality.

Organ pipe and organ stop are semantically related. In some cases you can use "Organ pipe" instead a noun phrase "Organ stop".

Organ pipe noun - The flues and stops on a pipe organ.

Organ stop and organ pipe are semantically related. Sometimes you can replace phrase "Organ stop" with "Organ pipe", this phrases are similar.