šnn / Semitic roots
Common Semitic noun *šinn-, tooth; denominative verb, to sharpen.
1. shin2, from Hebrew šîn, from Phoenician *šinn, tooth, twenty-first letter of the Phoenician alphabet, akin to Hebrew šēn, tooth. (The use of the word for "tooth" for this letter is the result of folk etymology and is based on the shape of the letter, which resembles a row of pointed teeth. The letter originally depicted a composite bow, a powerful kind of bow that is made of layers of different materials such as horn and wood and usually has the tips curving away from the archer when unstrung. The earlier name of the letter was *šann < *ṯann, "composite bow")
a. Sunna, from Arabic sunna, customary practice, tradition, from sanna, to sharpen, shape, prescribe;;
b. Sunni, from Arabic sunnī, Sunni, from sunna (see above).