IN

to be at the start of a new period, especially when important changes or new things happen, or to cause important changes to start happening

usher sth in

to ask someone to do a particular job

bring sb in

to get money or another advantage from an event or situation, often in an unfair way. Her family have been accused of cashing in on her death

cash in on sth

If one activity or event fits in with another, they exist or happen together in a way that is convenient.

fit in with sth

to begin-If the wound is untreated, infection may set in

set in

to include something when you are doing a calculation, or when you are trying to understand something

factor sth in

to become involved in a situation, story, or plan." We need expert advice, and that's where you come in" If a fashion or product comes in, it becomes available or popula.

come in

to include something as part of a plan, system, or agreement. "New safety regulations are being built into the proposal"

build sth in

to become involved in esp. something helpful

pitch in

If someone or something is boxed in, he, she, or it cannot move, because of other people or things that are too close or prevented from doing what you want to do

boxed in

to make something less or smaller or If an activity cuts into a period of time, it fills part of it, often a large part of it

cut into sth