When the word tenesmus is used without modification, it usually refers to rectal tenesmus.

Often, rectal tenesmus is simply called tenesmus.

Rectal tenesmus (when the word "tenesmus" is used by itself, this is usually what is meant)

Rectal tenesmus (Latin, from Greek teinesmos, from teinein to stretch, strain) is a feeling of incomplete defecation.

The term rectal tenesmus is a retronym to distinguish defecation-related tenesmus from vesical tenesmus.