Is FX an OTC derivative?

Could you please clarify for me if FX, or foreign exchange, qualifies as an over-the-counter derivative? I've been reading up on financial instruments and their classifications, but I'm still a bit hazy on this point. OTC derivatives are those traded directly between two parties, without going through an exchange, right? And FX transactions, being bilateral and often negotiated directly, seem to fit that definition. Am I understanding this correctly, or is there something I'm missing? Thank you for your help!