step in
To enter into some position, activity, or situation to intervene or improve it. We'd still be dealing with this mess if the manager hadn't stepped in and figured out a solution. We have a new marketing specialist stepping in to try and turn the company's profits around. You're here as an observer, but if you see a situation in the classroom, please step in.
step in (to the breach)
Fig. [for someone] to assume a position or take on a responsibility when there is a need or an opportunity to do so. The person who was supposed to help didn't show up, so I stepped into the breach. The manager stepped into the breach when Jane got sick.
step in(to some place)
to walk into a place. Tiffany stepped into the room and said hello to everyone. She stepped in to say hello.
step in
Enter into an activity or situation; also, intervene. For example, The business was doing poorly until Stan stepped in, or They are going to make a mess of the mailing unless someone steps in and shows them what to do . [Late 1400s] Also see step into.
step in
v.1. To enter into an activity or a situation: A substitute stepped in for the injured player.
2. To intervene: The government stepped in to end the strike.