7 (seven) is a positive integer following 6 and preceding 8. Its ordinal form is written "7th" or "seventh".
- In Greek-based number naming systems, 7 is associated with prefix hepta-, and with prefix septi- in Latin systems.
- Using the gag prefix, seven can be called gagtwo, since A(2,2) = 7.
- 7 is the last digit of Graham's number, and in fact it is the last digit of any power tower of 3's where the height of the tower is at least 2.
- A week has 7 days.
- The New Jersey metal band Symphony X composed and performed the song "Seven" as part of their album Paradise Lost.