grip on (something)

1. A good physical hold on something. In order to remove the bolt, I needed to get a grip on the wrench.

2. A newfound understanding of a topic or concept. The teacher spent extra time going over the material in class because she wanted her students to have a good grip on the subject matter before they took the exam.

get a grip on something

COMMON If you get a grip on a difficult situation, you start to understand it and take control of it. So far the country has failed to get a grip on its inflation rate. Note: You can also say that you take a grip on a situation with the same meaning. It is clear that the new leader has taken a grip on the party machine. Note: You can say that you keep a grip on a situation, meaning that you continue to understand and control it. Somehow, this corrupt band of politicians have managed to keep a grip on power.