Where did Leviticus and the Levites get their names?

The Levites

The Levites got their name from their ancestor: the Levites were the people who descended from Levi, one of Jacob’s twelve sons (Ex. 6:16ff.).¹

The Book of Leviticus

“Leviticus” is the English name for the third book of the Bible (its title in the Hebrew Bible is taken from the first word of the book: wayyiqrā’, “and he called”). The choice of name isn’t inspired (i.e., it isn’t from God),² but it is ‘a fairly appropriate title for the book for it deals largely with priestly matters, and the priests were drawn from the tribe of Levi’ (Deut. 18:1).³ “Leviticus” was the book’s name in the Septuagint (the early Greek version of the first five books of the Bible) and then in the Latin Vulgate, which is where the third book in the English Bible inherited the name “Leviticus” from.³

Notes
1. Levi was given his name by his mother, Leah. She called him Levi because she thought his birth, her third child with Jacob, would cause Jacob to finally become attached to her, love her (see Gen. 29:30,34; as the note in the ESV says, ‘Levi sounds like the Hebrew for attached‘).
2. Also see, ‘What does the name of each book of the Bible mean?‘
3. G. J. Wenham, The Book of Leviticus (Grand Rapids: Eerdmans, 1979), p. 3