Emily Dickinson Lexicon

ASSERT', v.t. [L. assero, assertum, to claim or challenge, to maintain or assert; of ad and sero. The sense of sero is to sow, properly to throw or set. To assert is to throw or set firmly.]

1. To affirm positively; to declare with assurance; to aver. – Milton.
2. To maintain or defend by words or measures; to vindicate a claim or title to; as, to assert our rights and liberties. – Dryden.