The word(s) "locks" appears 5 time(s) in 5 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) Bring me blocks of iron; until when he had filled up the space between the two mountain sides, he said: Blow, until when he had made it (as) fire, he said: Bring me molten brass which I may pour over it.

(2) And when he came to the water of Madyan, he found on it a group of men watering, and he found besides them two women keeping back (their flocks). He said: What is the matter with you? They said: We cannot water until the shepherds take away (their sheep) from the water, and our father is a very old man.

(3) Do they not then reflect on the Quran? Nay, on the hearts there are locks.

(4) The guilty shall be recognized by their marks, so they shall be seized by the forelocks and the feet.

(5) And send down (to prey) upon them birds in flocks,