Is my relationship polyamorous if my partners haven't met?

Am I in a polyamorous relationship if I’m seeing two people who do not know each other? But know of each other like they know I’m seeing other people?

Yes, that's polyamorous as long as they know about each other and are freely consenting to the arrangement. Your partners do not need to be connected romantically or otherwise for your relationship to be polyamorous. This arrangement is most frequently referred to as V or "Vee" polyamory.