وضوء
Wuḍūʾ
Washing before prayer: the minor wudu, the full bath (ghusl), and dry ablution (tayammum) where there is no water.
What it means
The Quran commands it before prayer: wash the face and the arms to the elbows, wipe the head, and wash the feet (5:6). A full bath is required after sexual intercourse and similar states. Where there is no water, clean earth may be used (4:43, 5:6). God “loves those who repent and those who purify themselves” (2:222).
What the sources say
The schools differ on small details. The Prophet is reported to have said that “cleanliness is half of faith” (Sahih Muslim).
Term and Arabic as listed in Ismail al Faruqi, Toward Islamic English (International Institute of Islamic Thought, 1995), p. 41, listed as GHUSL; p. 54, listed as WUḌŪ'. The definition is restated here.