What does effusive mean in geology ?

Effusive : definition

This term designates the volcanoes and volcanic phenomena involving a fluid lava, which will reach the surface and form lava flows or lava fountains. By extension, we speak of effusive rock for the materials resulting from the cooling of this fluid lava. Stromboli in the Aeolian Islands (Italy), Kilauea (Hawaii) as well as all the crater volcanoes of the Chaîne des Puys (France) are effusive volcanoes (in popular sciences we sometimes speak of red volcanoes).