רִיקּוּם, (רָקַם) formation of an embryo in an egg. Tosef. Ḥull. VIII, 20 וכמה הוא רִיקּוּמָהּ וכ׳ how far must the formation be advanced (to be called ביצה מרוקמת)? Until the chick can be seen through the egg.