The word(s) "mark" appears 15 time(s) in 15 verse(s) in Quran in Mohsin Khan translation.

(11) And We never sent before you (O Muhammad صلى الله عليه وسلم) any of the Messengers but verily, they ate food and walked in the markets. And We have made some of you as a trial for others: will you have patience? And your Lord is Ever All-Seer (of everything).

(12) Had We willed, We could have shown them to you, and you should have known them by their marks; but surely, you will know them by the tone of their speech! And Allah knows (all) your deeds.

(13) Muhammad (صلى الله عليه وسلم) is the Messenger of Allah. And those who are with him are severe against disbelievers, and merciful among themselves. You see them bowing and falling down prostrate (in prayer), seeking Bounty from Allah and (His) Good Pleasure. The mark of them (i.e. of their Faith) is on their faces (foreheads) from the traces of prostration (during prayers). This is their description in the Taurat (Torah). But their description in the Injeel (Gospel) is like a (sown) seed which sends forth its shoot, then makes it strong, and becomes thick and it stands straight on its stem, delighting the sowers, that He may enrage the disbelievers with them. Allah has promised those among them who believe (i.e. all those who follow Islamic Monotheism, the religion of Prophet Muhammad صلى الله عليه وسلم till the Day of Resurrection) and do righteous good deeds, forgiveness and a mighty reward (i.e. Paradise).

(14) marked by your Lord for the Musrifun (polytheists, criminals, sinners - those who trespass Allah's set limits in evil-doings by committing great sins).

(15) The Mujrimun (polytheists, criminals, sinners) will be known by their marks (black faces), and they will be seized by their forelocks and their feet.