is a small nation that is an internationally recognized sovereign state
and San Marino
are all microstates.
In terms of population the most extreme example is the Pitcairn Islands, with ca. 47 inhabitants. It is considered a separate country, though a dependent area of the United Kingdom.
The term microstate is sometimes used as a synonym for micronation. The distinction is that micronations are not generally recognised as sovereign states except by other micronations.
See also: List of countries by population and List of countries by area.
Microstate is also used in thermodynamics to refer to a specific configuration of particles of a material: see microstate (thermodynamics).