“Point of interest” is a general term for a real world point-like feature noteworthy enough to include it on a map. Some examples are restaurants, cafés, shops, banks, churches, public toilets and water fountains. There’s not a single point of interest tag key in OpenStreetMap but a variety that can be used for mapping a point of interest: amenity=
, shop=
, tourism=
are some examples.
OpenStreetMap Wiki: Key:amenity, Key:tourism, Key:shop, Key:leisure