עֵד (ʻêdaydnoun|femininemenstruation)
[Heb] עֵד, עִדָּה ETCBC: עִדָּה‎ (subs|menstruation) OSHL: p.ap.ab TWOT: 1564a GK: H6340
Derivation: from an unused root meaning to set a period (compare עָדָה, עוּד);
Strong's: the menstrual flux (as periodical); by implication (in plural) soiling
KJV: filthy.