The term 'allow to enter' can be expressed in three different ways: ADMIT (5 letters), Intromit (8 letters), and Letin (5 letters). ADMIT is a verb meaning to accept or acknowledge something, such as admitting one's guilt. Intromit is a verb meaning to introduce or allow something to enter, such as intromitting a new idea into a discussion. Finally, Letin is a verb meaning to allow someone to enter, such as letting someone in through a door. All three terms express the same concept of allowing something or someone to enter.