The term 'CROSSES A THRESHOLD' can be solved by the word 'ENTERS'. This phrase is often used to describe someone or something crossing a physical or metaphorical boundary. It can be used to describe a person entering a new stage of life, such as a graduation ceremony, or a person entering a new place, such as a new home. It can also be used to describe a situation that has reached a certain point, such as a company reaching a certain level of success.