reckon

Concise Oxford English Dictionary © 2008 Oxford University Press:
reckon/ˈrekən/

▶verb

• 1 calculate.

• 2 be of the opinion.

• 3 regard in a specified way.

  ■ (reckon someone/thing among) include someone or something in (a group).

  ■ (reckon on/to) informal have a specified view or opinion of.

• 4 (reckon on) rely on or be sure of.

  ■ expect.

• 5 (reckon with (or without)) take (or fail to take) into account.

• 6 (reckon with) archaic settle accounts with.

– phrases
a —— to be reckoned with (or to reckon with) a thing or person not to be ignored or underestimated.

– origin OE (orig. ‘give an account of items received’, hence the notion of ‘calculation’) (ge)recenian ‘recount, relate’, of W. Gmc origin.