Kathalika (nt.) [der. uncertain], always in combn pād'- odaka pāda -- pīṭha pāda -- k˚: either a cloth to wipe the feet with after washing them, or a footstool Vin i.9, 47; ii.22 sq., 210, 216. At VvA 8 however with pāda -- pīṭha expld as a footstool (pāda -- ṭhāpana -- yoggaŋ dārukhaṇḍaŋ āsanaŋ). Bdhgh (on CV ii.1.1) expld pādapīṭha as a stool to put the washed foot on, pāda -- kathalika as a stool to put the unwashed foot on, or a cloth to rub the feet with (ghaŋsana).
  the meaning "bowl" seems to be preferable to Bdhgh's forced interpretation as "towel."

Pali-English Dictionary, TW Rhys Davids, William Stede,