Visualise
Part of speech: verb
Definition: To envisage, or form a mental picture (of something).
Visualize
Part of speech: verb
Definition: To envisage, or form a mental picture (of something).To make (something) visible.
Example sentence: I think in order to accomplish anything in life, you have to visualize yourself there - accepting the award, hearing your song on the radio, whatever it is - or you lose the willpower and the drive.