the way you hold something or your ability to hold it [= grip]:
Luke took her arm in a firm grasp and led her through the gate.
He had allowed the ball to slip from his grasp.
your ability to understand a complicated idea, situation, or subject [= understanding]
Her grasp of the issues was impressive.
a good/firm/thorough etc grasp of something
Steve has a good grasp of the European legal system.
After two months, his grasp on the subject was improving.
your ability to achieve or gain something
within somebody's grasp
An agreement to end the war seemed within their grasp.
beyond somebody's grasp
Many families are finding suitable housing beyond their grasp.
control or power:
The king was determined not to let Scotland slip from his grasp.