Semitic word root √kpp
The Semitic root √kpp has the basic meaning of being “curved” or “bent” into a hollow form. A derived meaning is to make other people bow down. It might be related to Egyptian √kȝp, since there we find the meaning of covering with curved wings.
Curving and bending down
Hebrew kpp = bend
כפף kpp kaphaph : to bend, bend down, be bent or bowed — Old Hebrew (Strong)
Akkadian kpp = bend, curve
𒄃𒃵 kapāpu : to bend, curve, bow; to be curved, bent; to surround sth. with sth.; to bend, twist; to be bent, curved; to make bow down; to be bent, twisted — Akkadian (AAF)
Egyptian kpp = cover
Curved, hollow things
Most often found are hands, soles, fronds, bowls, and stones. There are many words for stones, but this one emphasizes a curved form, such as with difficult to climb terrain. A famous term is the cap called kippah.
Hebrew kp = palm of hand, palm frond, curved things
כף kp kaph : hollow or flat of the hand, palm, sole of the foot, a pan — Old Hebrew (Strong)
כפה kph kippah : a branch, frond (of a palm tree) — Old Hebrew (Strong)
כפור kpwr kephor : bowl, basin — Old Hebrew (Strong)
כף kp keph : a rock, rocks — Old Hebrew (Strong)
כפה kph kippah : The cloth skullcap or yarmulke traditionally worn by male Jews. — Hebrew (Wikt)
Akkadian kp = palm of hand, palm frond, curved things
Ugaritic kpp = palm of hand
𐎋𐎔𐎔 kpp : hand, palm — Akkadian (AAF)
Egyptian kp = palm of hand, sole of foot
Making people bow down
Just as in English, making people bow to your will is expressed as figuratively bending them.
Hebrew kp = subdue, forcing, bending people
Aramaic kp = subdue, forcing, bending people
Akkadian wkl = overseeing; written like kp
The very same spelling for “palm frond” is with a different reading used for “overseer”.
𒉺 waklu : overseer, foreman, instructor — Akkadian (Wikt)