Definition of aerocyst in English:

aerocyst

noun

Botany
rare
  • An air bladder of a seaweed.

Origin

Mid 19th century; earliest use found in John Lindley (1799–1865), botanist and horticulturist. From aero- + cyst, after French aérocyste.

Pronunciation:

aerocyst

/ˈɛːrə(ʊ)sɪst/