A more thorough explanation:

Definition: Secession is the act of withdrawing from a group or organization, especially a religious or political one.

Example 1: The secession from the established church.

Example 2: The secession of 11 states at the time of the Civil War.

Example 1 refers to the act of withdrawing from a religious association, while Example 2 refers to the act of withdrawing from a political association. Both examples illustrate the definition of secession, which is the process of leaving a group or organization.