admission / admittance
Acceptance vs. physical entry.
Admission has four senses: physical entry to a place, acceptance into a group or institution, the price of entry, and a confession, as in admission to the stadium, admission to the college, and an admission of guilt. The narrower word, admittance, means only physical entry, as in the sign No Admittance, and it is now rare outside signs and formal notices. For physical entry, either word is standard.
Examples
Use Admission to the museum is ten dollars. (the price of entry)
Use Her admission that the figures were wrong ended the debate. (a confession)
Use The sign on the lab door read No Admittance. (physical entry)
Avoid He gained admittance to the law program. (admittance is only for physical entry, and acceptance into a program isn’t physical entry)