3. Entrance, admittance, admission refer to the possibility of entering a place or a group. Entrance may refer to either possibility: Entrance is by way of the side door; entrance into a card game. Admittance refers more to place and suggests entrance that may be permitted or denied: to gain admittance to a building; no admittance. Admission refers more to special groups and suggests entrance by payment, by formal or special permission, privilege, and the like: admission to a concert, a game, to candidacy, the bar, to society.

Did you mean entrenchment?