have a grip on (something)

have a grip on (something)

1. Literally, to have a strong physical hold on something. In order to remove the bolt, you'll need to have a grip on the wrench.
2. By extension, to have control of something. The generals project that they can have a grip on the region in six months, but I think that's a conservative estimate—the area will be under our control in weeks, by my reckoning.
3. To have 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 grip on the subject matter before they took the exam.
See also: grip, have, on