A slow jam is an umbrella term for music with R&B and Soul influences. Slowjams are commonly R&B ballads or downtempo songs. The term is most commonly reserved for soft-sounding songs with heavily emotional or romantic lyrical content.
Guy 1: I love this. What is it?
Guy 2: Its a soul jam. Duh.
Guy1: A What?
Guy 2: R&B and Soul idiot