On both Rikaikun, Jisho, and wikipedia, this shows as spine/backbone.
It’s a level 22 radical, level 52 kanji, both times reads as bath. That’d be fine for the radical, but doesn’t seem like it makes sense for the kanji, since the kanji for bath is
and on its own, 呂 doesn’t seem to mean bath?
(The 湯 kanji seems to mean bath, but only really with other kanji in combination? But it is listed as a meaning.)
This seems like an error.