Boyd’s Bible Dictionary:
To wash, a sign of hospitality
(Gen. 18:4; 1 Sam. 25:41; John 13:5-6). To remove shoes, a reverence (Ex. 3:5); sign of mourning (Ezek. 24:17).
Strong’s Dictionary of Greek Words:
Meaning:
dative case feminine of a derivative of 4228 (as adverb); foot-wise, i.e. by walking