생리가 · 생리를 · 생리 중이에요
period, menstruation
Example
생리 중이라서 배가 좀 아파요.
I'm on my period, so my stomach hurts a bit.
Word parts
생 life+리 principle
Literally 'life principle', i.e. a body function; it also means 'physiology' (생리학).
Good to know
Pronounced [생니]. The normal, neutral word, fine with a pharmacist or doctor. Period pain is 생리통.