(of genu, "knee," and fleo "I bend,") the act of bowing or bending the knee; or rather of kneeling down.
The Jesuit Roefweyd, in his Onomasticon, shows, that genuflexion, or kneeling, has been a very ancient custom in the church, and even under the Old Testament dispensation; and that this practice was observed throughout all the year, excepting on Sundays, and during the time from Easter to WhitSunday, when kneeling was forbidden by the council of Nice.
Others have shown, that the custom of not kneeling on Sundays had obtained from the time of the apostles, as appears from St Irenaeus, and Tertullian; and the Genus Ethiopic church, scrupulously attached to the ancient ceremonies, still retains that of not kneeling at divine service. The Ruffians esteem it an indecent posture to worship God on the knees. Add, that the Jews usually prayed standing. Roefweyd gives the reasons of the prohibition of genuflexion on Sundays, &c., from St Basil, Anastasius, St Justin, &c.
Baronius is of opinion, that genuflexion was not established in the year of Christ, 38, from that passage in Acts xx. 36, where St Paul is expressly mentioned to kneel down at prayer; but Saurin shows, that nothing can be thence concluded. The same author remarks, also, that the primitive Christians carried the practice of genuflexion so far, that some of them had worn cavities in the floor where they prayed: and St Jerome relates of St James, that he had contracted a hardness on his knees equal to that of camels.