Klein Dictionary, כ

כ The eleventh letter of the Hebrew alphabet. The name of this letter, ‘Kaph’, means ‘hollow of the hand’; so called in allusion to the ancient Heb. form of this letter. It has a final form ך. In PBH כ has the numerical value of twenty, and ך has the numerical value of five hundred. כ alternates with ג (see the introductory article to letter ג) and with ק; cp. e.g. קוֹבַע, secondary form of כּוֹבַע (= helmet), and כשׁט, a collateral base of קשט (= to make straight, to arrange, to adorn, decorate, ornament, embellish). See קשׁט ᴵ and תַּכְשִׁיט.