Class Cycadopsida is a group of seed plants that are characterized by their large pinnate leaves and stout stem. Some synonyms for Class Cycadopsida include Cycadophyta and Cycadales. The word Cycadophyta comes from the Greek words kykas, meaning palm, and phuton, meaning plant. The term Cycadales is derived from the Greek word kykas, meaning palm, and adales, meaning resemblance. These synonyms are used interchangeably to refer to the group of plants that are commonly known as cycads. Cycadopsida is one of the oldest surviving lineages of seed plants and are often referred to as "living fossils" due to their ancient origin.