English
masturbatorium
From masturbat(e) + -orium.
Formed from masturbate + -orium
Latin masturbātus ‘having masturbated’
English masturbate
The story
Modelled after auditorium, sanatorium, etc.
Today it means
noun A room in which a person masturbates; for example, a private room in a clinic where a sperm donor masturbates to produce semen.
Language periods are conventional ranges, not dates for this word.
Etymograph / masturbatorium