כָּדַר (v. כַּד II) to be arched, rounded. Ab. Zar. 40ᵃ; Ḥull. 64ᵃ (sign of eggs of clean birds) כל שכּוֹדֶרֶת ועגולגולת (Var. קוֹדֶרֶת, קוֹדֶדֶת, כּוֹדֶדֶת) that which is arched (on top not pointed) and rounded (rolling); Tosef. ib. III (IV), 23.
Hithpa. - הִתְכַּדֵּר (v. כַּדּוּר) to be thrown around in a circle of players. Koh. R. to XII, 11 מה הכדור הזה מִתְכַּדֵּר וכ׳ as the ball is thrown around from hand to hand.