To be acquainted with. (Apparently it compares with French: connaitre, German kennen and dialect English ken)
Znam Dave - I know Dave.
Znam to dziecko - I know this children.
Znam to słowo - I know this word.
Wiem, że... - I know that...
Wiedzą, kto... - They know who...
Wiesz, jakie... - You know what kind of...
Wiem wszystko - I know everything
Nic nie wiem - I don't know anything
Careful with umieć, meaning to know how to.
Umiem pływać - I know how to swim
Albo and lub, I think are completely interchangable. Just use the one that you feel like using at the time. Albo might be more popular in everyday speech, but who am I to know?