determine
de-ter-mine
verb
To decide firmly and resolutely to do something specific or achieve a goal.
"She determined to finish the marathon despite the pain."
verb
To find out or establish something precisely after investigation or calculation.
"Scientists worked to determine the cause of the illness."
Thesaurus
Synonyms: regulate, influence, shape, mould, mold, limit, set, define, fix, specify, decide, make up one's mind