It can refer to:
* The seventh in a series or sequence: "La séptima vez que lo intenté, finalmente lo conseguí" (The seventh time I tried, I finally got it).
* The seventh part of something: "Un séptimo de la pizza" (One seventh of the pizza).
* Seventh grade: "Estoy en séptimo grado" (I am in seventh grade).
It's also a common element in musical terminology, referring to a musical interval.