The word(s) "proof" appears 60 time(s) in 58 verse(s) in Quran in Muhammad Pickthal translation.

(31) With clear proofs and writings; and We have revealed unto thee the Remembrance that thou mayst explain to mankind that which hath been revealed for them, and that haply they may reflect.

(32) And verily We gave unto Moses nine tokens, clear proofs (of Allah's Sovereignty). Do but ask the Children of Israel how he came unto them, then Pharaoh said unto him: Lo! I deem thee one bewitched, O Moses.

(33) He said: In truth thou knowest that none sent down these (portents) save the Lord of the heavens and the earth as proofs, and lo! (for my part) I deem thee lost, O Pharaoh.

(34) They said: We choose thee not above the clear proofs that have come unto us, and above Him Who created us. So decree what thou wilt decree. Thou wilt end for us only this life of the world.

(35) And they say: If only he would bring us a miracle from his Lord! Hath there not come unto them the proof of what is in the former scriptures?

(36) Or have they chosen other gods beside Him? say: Bring your proof (of their godhead). This is the Reminder of those with me and those before me, but most of them know not the Truth and so they are averse.

(37) He who crieth unto any other god along with Allah hath no proof thereof. His reckoning is only with his Lord. Lo! disbelievers will not be successful.

(38) Is not He (best) Who produceth creation, then reproduceth it, and Who provideth for you from the heaven and the earth? Is there any Allah beside Allah? Say: Bring your proof, if ye are truthful!

(39) Thrust thy hand into the bosom of thy robe it will come forth white without hurt. And guard thy heart from fear. Then these shall be two proofs from your Lord unto Pharaoh and his chiefs. Lo! they are evil-living folk.

(40) And We shall take out from every nation a witness and We shall say: Bring your proof. Then they will know that Allah hath the Truth, and all that they invented will have failed them.