This is the 3867th most frequent Polish word.
poznaj
"Poznaj" means "get to know" or "meet" in English.
Here, 'poznaj' is used as an imperative to suggest becoming acquainted with someone.
Poznaj swojego sąsiada.
Get to know your neighbor.
In this context, 'poznaj' in its inflected form 'poznał' conveys the meaning of learning or discovering knowledge about something.
Chcę, abyś poznał jej historię.
I want you to learn her story.
Here 'poznałaś' is a past tense form of 'poznaj', meaning 'to have met' or 'become acquainted with' someone.