simple past tense and past participle of reckon for

One who reckons. / (archaic) An accountant; one who computes or calculates.

Able to be reckoned or computed.

plural of ready reckoner

plural of stepped reckoner

A method of estimating the position of a ship or aircraft by applying estimates of the distance and direction travelled to a previously known position. In respect to ships/boats, it excludes the effect of wind and current on the vessel. Compare with estimated position. Abbreviation: DR

Used other than figuratively or idiomatically: see reckon, without. / To ignore; to fail to consider.

Synonym of reckon on

(idiomatic, uncommon, archaic) A (falsified) bill that is not itemised, and that is unjustifiably high. / (nautical) A false or incorrect reckoning of position.

(historical, UK, military) An allowance formerly made to certain British officers from the money appropriated for army clothing.