Definition of reckon verb from the Oxford Advanced Learner's Dictionary

Oxford3000

reckon

verb
ˈrekən
 
; ˈrekən
 
 
1 [transitive, intransitive] reckon (that)… (informal, especially British English) to think something or have an opinion about somethingI reckon (that) I'm going to get that job.He'll be famous one day.What do you reckon(= do you agree)?It's worth a lot of money, I reckon.‘They'll never find out.’ ‘ You reckon?(= I think you may be wrong about that)2 be reckoned [transitive] (not used in the progressive tenses) to be generally considered to be somethingreckon to be/have something Children are reckoned to be more sophisticated nowadays.+ noun/adjective It was generally reckoned a success.3 [transitive] reckon to do something (British English, informal) to expect to do somethingWe reckon to finish by ten.He wasn't reckoning to pay so much.4 [transitive] to calculate an amount, a number, etcreckon something (at something) I could see him reckoning the cost as I spoke.The age of the earth is reckoned at about 4600 million years.reckon (that)… They reckon (that) their profits are down by at least 20%.be reckoned to do something The journey was reckoned to take about two hours.
Idioms
see
a name to reckon with at name n.
Phrasal verbs

reckon on something

to expect something to happen or to rely on something happeningThey hadn't reckoned on a rebellion.reckon on doing something We'd reckoned on having good weather.

reckon something up

(especially British English) to calculate the total amount or number of somethingHe reckoned up the cost of everything in his mind.

reckon with somebody/something

1 [usually passive] to consider or treat somebody/something as a serious opponent, problem, etcThey were already a political force to be reckoned with.2 (usually used in negative sentences) to consider something as a possible problem that you should be prepared for
Synonym
take something into account
reckon with doing something I didn't reckon with getting caught up in so much traffic.

reckon without somebody/something

(especially British English) to not consider somebody/something as a possible problem that you should be prepared for
Synonym
not take something into account
They had reckoned without the determination of the opposition.
Usage noteUsage note: thinkbelieve feel reckon be under the impressionThese words all mean to have an idea that something is true or possible or to have a particular opinion about somebody/something.think to have an idea that something is true or possible, although you are not completely certain; to have a particular opinion about somebody/something:Do you think (that) they'll come? Well, I like it. What do you think?believe to have an idea that something is true or possible, although you are not completely certain; to have a particular opinion about somebody/something:Police believe (that) the man may be armed.think or believe?When you are expressing an idea that you have or that somebody has of what is true or possible, believe is more formal than think. It is used especially for talking about ideas that other people have; think is used more often for talking about your own ideas:Police believe… I think… When you are expressing an opinion, believe is stronger than think and is used especially for matters of principle; think is used more for practical matters or matters of personal taste.feel to have a particular opinion about something that has happened or about what you/somebody ought to do:We all felt (that) we were unlucky to lose.reckon (informal) to think that something is true or possible:I reckon (that) I'm going to get that job.be under the impression that… to have an idea that something is true:I was under the impression that the work had already been completed.to think/believe/feel/reckon/be under the impression that…It is thought/believed/reckoned that…to be thought/believed/felt/reckoned to be somethingto think/believe/feel something about somebody/somethingto sincerely/honestly/seriously/mistakenly think/believe/feel