Academic or medical term for the biological functions of living organisms.
He is majoring in physiology at university.
Common euphemism for menstruation; used in everyday conversation and health contexts.
See also: 月経
My period is late, so I'm a little worried.
My period hasn't come yet this month.
My period is heavy and it's really tough.
It's best to avoid intense exercise during one's period.
menstrual pain; period pain
menstrual irregularity; irregular periods