• Confession, generally.
• Ticket to enter an event or movie theater
• University and college admissions
• Changes in status allowing an entity to become part of a group, see List of U.S. states by date of statehood

In law:

• Admission (law), a statement that may be used in court against the person making it.
• Admission to the bar, change in status allowing an applicant to become part of a profession
• Admissibility is an attribute of evidence (law)

In science and engineering:

• Admittance, an electrical engineering term - the admittance (Y) is the inverse of the impedance (Z).