Definition of meristem in US English:



  • A region of plant tissue, found chiefly at the growing tips of roots and shoots and in the cambium, consisting of actively dividing cells forming new tissue.

    ‘the apical meristem of the shoot produces the embryonic seed leaves’
    • ‘Leaves communicate photoperiodic signals to meristems, stolons and buds in flowering, tuberization and dormancy.’
    • ‘These embryos had organized root meristems and apical shoot meristems flanked by the developing cotyledons.’
    • ‘The developmentally accumulated proteins localized to early differentiating, but not the highly dividing, regions of the root and shoot apical meristems.’
    • ‘Plant growth originates from meristems, localized tissues with stem cell features that are at the origin of all organs of the plant.’
    • ‘This condition can also be due to restricted diffusion of oxygen into internal tissues or high rates of cellular metabolism, as in actively dividing cells of meristems.’


Late 19th century: formed irregularly from Greek meristos ‘divisible’, from merizein ‘divide into parts’, from meros ‘part’. The suffix -em is on the pattern of words such as xylem.