air mattress: a mattress that can be stored flat and inflated for use
mattress: a large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed
gnetopsida: gymnospermous flowering plants; supposed link between conifers and angiosperms; in some systems classified as a class (Gnetopsida) and in others as a subdivision (Gnetophytina or Gnetophyta)