From kathath; beaten, i.e. Pure (oil):
see HEBREW kathath
H3795. kathith
כָּתִית adjective beaten; — only in combination כָּתִית שֶׁמֶן beaten oil, i.e. oil made by beating or pounding the olives in a mortar; especially fine and costly (compare LevyNHWB ii. 443 below כָּתִית); — 1 Kings 5:25; Exodus 29:40; Numbers 28:5; כ זָךְ זַית ׳שֶׁמֶן לַמָּאוֺר Exodus 27:20 pure beaten olive oil for the lamp = Leviticus 24:2 (Hexateuch only H, P).