Strong’s Hebrew 3801. כֻּתֹּנֶת
Definition: Tunic. Inner garment – worn next to the skin. Likely related to a Semitic word for linen (although the garment could be made of other materials like wool or silk).
Translated as the Chiton (Khiton) of the Greeks (compare the word Khiton to Khethoneth).
The first mention of this word is in Genesis 3:21, when God makes Adam & Eve kethoneths out of animal skin to replace their fig leaf loincloths.
Joseph’s “coat of many colors” was a kethoneth. The white linen tunics of the priests and High Priest were kethoneths.
See also II Samuel 13:18,19, Job 30:18 and Song of Solomon 5:3.