Wudu is a ritual purification process in Islam that involves cleansing certain parts of the body. It is a mandatory act of worship that Muslims must perform before prayer. The four mandatory acts of Wudu are washing the face, then the arms, then wiping the head, and finally washing or wiping the feet, and these acts must be done in order without any big breaks between them. The process of Wudu is governed by fiqh (Islamic jurisprudence), which specifies rules concerning hygiene and defines the rituals that constitute it.

The steps to perform Wudu are as follows:

1. Begin by saying ‘Bismillah’.
2. Wash your hands up to the wrists thoroughly three times.
3. Rinse your mouth three times, swirling the water around, and rinse your nose three times, blowing the water out using the left hand to remove the water from your nose.
4. Make your intention that you are now performing the fard (obligatory) actions of Wudu.
5. Wash your face three times, from the hairline to the chin and from ear to ear.
6. Wash your arms three times, up to the elbow, starting with the right arm.
7. Wipe your head once with wet hands, passing them over the head from the forehead to the back of the head.
8. Wash your feet three times, up to the ankles, starting with the right foot.

Activities that invalidate Wudu include urination, defecation, flatulence, deep sleep, light bleeding (depending on madhhab), menstruation, postpartum, and sexual intercourse.

Wudu is often translated as partial ablution, as opposed to ghusl as full ablution where the whole body is washed. It also contrasts with tayammum (dry ablution), which uses sand or dust in place of water, principally due to water scarcity or other harmful effects on the person. Purification of the body and clothes is called taharah.