noun-modifying (irregular)
sinoatrial
Anatomical term used prenominally, as in 洞房結節 (sinoatrial node).
inner bedroom; brothel
Archaic. Originally referred to an inner room or bedroom; later also used euphemistically for a brothel. Not used in modern Japanese.
The sinoatrial node acts as the heart's pacemaker.
In old documents, there are examples where 洞房 is used to mean an inner bedroom.
In Edo-period literature, 洞房 sometimes euphemistically referred to a brothel.