Yes, mark is a Scrabble word!

Verb

1. Attach a tag or label to

2. Designate as if by a mark

3. Be a distinctive feature, attribute, or trait; sometimes in a very positive sense

4. Mark by some ceremony or observation

5. Make or leave a mark on

6. To accuse or condemn or openly or formally or brand as disgraceful

7. Notice or perceive

8. Mark with a scar

9. Make small marks into the surface of

10. Establish as the highest level or best performance

11. Make underscoring marks

12. Remove from a list

13. Put a check mark on or near or next to

14. Assign a grade or rank to, according to one's evaluation

15. Insert punctuation marks into

Noun

1. A number or letter indicating quality (especially of a student's performance)

2. A distinguishing symbol

3. A reference point to shoot at

4. A visible indication made on a surface

5. The impression created by doing something unusual or extraordinary that people notice and remember

6. A symbol of disgrace or infamy

7. Formerly the basic unit of money in Germany

8. Apostle and companion of Saint Peter; assumed to be the author of the second Gospel

9. A person who is gullible and easy to take advantage of

10. A written or printed symbol (as for punctuation)

11. A perceptible indication of something not immediately apparent (as a visible clue that something has happened)

12. The shortest of the four Gospels in the New Testament

13. An indication of damage

14. A marking that consists of lines that cross each other

15. Something that exactly succeeds in achieving its goal