1. A solvent or dissolving substance, so called by the alchemists from some supposed connexion of its action with the changes of the moon.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• nenstruum,
• kenstruum,
• jenstruum,
• mwnstruum,
• msnstruum,
• mdnstruum,
• mrnstruum,
• m4nstruum,
• m3nstruum,
• mebstruum,
• memstruum,
• mejstruum,
• mehstruum,
• mensturum,
• mensstruum,
• Manstruum,
• Mensurtum,
• Mensutrum,
• Mensutruum,
• Mensutrumm

• menstruation,
• muenster,
• menstruate,
• menstruating,
• menstrual.

The adjective form of "menstruum" is "menstrual".