In 2020, there were many ways to understand the year in music; this week, we're considering four. Dance music is a communal and carnal act, a collective catharsis charged by pulsing beats and sweating bodies. What cruel irony that 2020 produced such body-rockin' hits as dance floors stood empty. By the same token, a wide spectrum of dance music — pop, reggaeton, house, K-pop, J-pop, disco, hyperpop, R&B — transformed bedrooms into clubs, kitchens into discotheques and backyards into glow-stick raves.