The term has no singular definition. But simply put, it’s an ideology rooted in its opposition to capitalism and wanting to shift power from corporations to workers.

Zohran Mamdani declared victory in New York City’s Democratic mayoral primary Tuesday night after Andrew Cuomo conceded the race in a stunning upset. Mamdani is a progressive upstart who was virtually unknown when the contest began built a substantial lead over the more experienced but scandal-scarred former governor.

The 33-year-old democratic socialist’s upset win in New York signals a potential shift in city politics — and maybe beyond.