Meaning of “visualize” - Learner’s Dictionary

visualize

verb [ T ] also UK -ise us uk /ˈvɪʒuəlaɪz/

to create a picture in your mind of someone or something:

I was very surprised when I met Geoff - I'd visualized someone much older.
visualization noun [ U ] us uk /ˌvɪʒuəlaɪˈzeɪʃən/

(Definition of “visualize” from the Cambridge Learner’s Dictionary © Cambridge University Press)