forereckoning

Etymology 1
From.

Etymology 2
From.

Noun

 * 1) Precalculation; foreplanning
 * 2) * 1948, The Restless Voyage:
 * had to have sleep, but decided that since I could not afford to be wrong in my forereckoning, I would at those times guard against surprise by leaning a heavy stick against the bar so that the latter's displacement would cause it to fall and wake