No. Postgres has in-memory bitmap indexes, which are built on the fly while scanning the index and used to more efficiently combine AND/OR clauses, but that's not quite the same thing. There have been several attempts at adding on-disk bitmap index support to Postgres, but they've all been abandoned.

BRIN indexes are kind of bitmap like...

Looks like PostgreSQL only has ephemeral bitmap indexes used when making a query that combines multiple indexes - https://leopard.in.ua/2015/04/13/postgresql-indexes - https://www.postgresql.org/docs/current/indexes-bitmap-scans...