What is the meaning of Seize_upon?

To grasp or take hold of (an object) suddenly, forcibly, or tightly.

To take up, embrace, enact, or turn eagerly to (a plan, idea, ideology, cause, practice, method, etc.); to grasp, understand, and accept quickly; to adopt wholeheartedly or vigorously.

To take possession of or claim (an idea, person, event, etc.) as one's own; to assimilate, absorb, annex, co-opt.

Source: wiktionary.org