Definition of tomentum in US English:



  • A layer of matted woolly down on the surface of a plant.

    • ‘With its thick tomentum and indumentum and its pointed dark green leaves, with its dense growth habit, and with its pretty flowers, it is a major asset to any garden.’
    • ‘Leaves lack the thick tomentum beneath the leaf that characterizes the white linden.’
    • ‘The back of its leaves is covered with grayish-white tomenta.’
    • ‘Setae type range from being thin and highly branched, forming dense tomenta, to being broad and spatulate.’
    • ‘The leaves of O. colensoi are sparingly tomentose on the upper surface of the young leaves, but the tomentum disappears before the leaves are fully developed.’


Late 17th century: from Latin, literally ‘cushion stuffing’.