Definition of fucoid in US English:



  • A brown seaweed or fossil plant of a group to which bladderwrack belongs.

    Order Fucales, class Phaeophyceae, including genus Fucus

    • ‘It is well known that most fucoids are prevented from establishing on exposed shores by limpet grazing.’
    • ‘Without grazers to remove them, the faster growing epiphytes could outcompete fucoids by covering all surfaces or at least covering enough surface area to decrease photosynthetic activity of Fucus.’
    • ‘This suggests a rapid, recent evolution of at least northern hemisphere temperate fucoids.’
    • ‘They found, however, no difference in attachment strength between Fucus evanescens and the native fucoids when plants of the same size were compared.’
    • ‘However, since F. evanescens did not exclude other fucoids in its new range, its effect on the recipient biota is probably small.’


  • Relating to or resembling a brown seaweed, especially a fucoid.

    • ‘It was covered in fucoid algae and delicate yellow and orange plumose anemones that drew us in closer, as there were often a few gems nestling in them.’
    • ‘Ceratopteris spores, like fucoid zygotes, divide unequally to produce a small rhizoid cell and a larger cell that develops into the thallus.’
    • ‘In the fucoid zygote, polarization events can be triggered by a range of stimuli, including unidirectional light and fertilization.’
    • ‘The zygotes of the fucoid brown algae have long been studied by developmental biologists in an effort to understand how cellular polarity arises.’


Mid 19th century: from fucus + -oid.