Meaning : To believe especially on uncertain or tentative grounds.
Example :
Scientists supposed that large dinosaurs lived in swamps.
Synonyms : conjecture, hypothecate, hypothesise, hypothesize, speculate, suppose, theorise
Meaning : Construct a theory about.
Example :
Galileo theorized the motion of the stars.
Meaning : Form or construct theories.
Example :
He thinks and theorizes all day.