ركع
Rakaʿa
To bow in worship, as required in Islamic worship; the root of rukūʿ and rakʿah.
What it means
Rakaʿa is the Arabic verb for bowing in worship. In the salah it names the act of bending from the standing position, with the hands resting on the knees, while saying words of praise to God. The same root gives rukūʿ and rakʿah. The Quran commands believers to establish the prayer, give zakah and bow with those who bow (2:43). It also tells them to bow and prostrate themselves and worship their Lord (22:77). Faruqi renders the word as kneeling, though the act in the prayer is a bow, and the sense is humble submission before God.
Often misunderstood as
That it means kneeling, when the movement in the salah is a bow from standing.
Term and Arabic as listed in Ismail al Faruqi, Toward Islamic English (International Institute of Islamic Thought, 1995), p. 34, listed as RAKA'A. The definition is restated here.