Reckon  v. 1 (often foll. By that) be of the considered opinion; think. 2 consider or regard (reckoned to be the best). 3 count or compute by calculation. 4 (foll. By in) count in or include in computation. 5 make calculations; add up an account or sum. 6 (foll. By on) rely on, count on, or base plans on. 7 (foll. By with or without) take (or fail to take) into account. [old english]