Silurian definition

Of, relating to, or being the period of geologic time from about 443 to 416 millions years ago, the third period of the Paleozoic Era. The Silurian Period is characterized by the development of jawed fishes, early invertebrate land animals, and land plants.

The Silurian Period.

Of the Silures.

Designating or of the third geologic period of the Paleozoic Era, characterized by the development of coral reefs and small land plants, the first fish with jaws, and the first land arthropods.

The third period of the Paleozoic Era, from about 438 to 408 million years ago. During this time glaciers that formed during the late Ordovician melted, causing sea levels to rise. The first coral reefs, fish with jaws, and freshwater fish appeared, and jawless fish continued to spread rapidly. The first vascular plants also appeared, as did land invertebrates including relatives of spiders and centipedes.