How to Sign "Understand" in American Sign Language (ASL)

In ASL, "understand" is signed by forming your dominant hand into the letter "C" shape, placing it near your forehead with your palm facing in, then moving it forward and down while closing the "C" into a fist. This shows how we grab ideas. You can tap your forehead with the "C" hand before moving it forward if you want. The sign can be changed to show how well you understand something, from just getting it a little to really knowing it deeply. People often do it fast when talking with friends, but in class or meetings, they might sign it slower to show they truly understand.