Definition of gerontic in English:

gerontic

adjective

  • Relating to old age, elderly people, or senescent animals or plants.

    • ‘A few large specimens were known in 1986, however, these were thought to represent gerontic individuals.’
    • ‘This interpretation is also indirectly supported by the close stratigraphic occurrence (Early and Middle Devonian) of these gastropod genera having such an unusual gerontic aperture.’
    • ‘The increasingly low relief of the anterior border with a narrow curvature of the anterior border furrow close to the anterior branches of the facial suture is certainly a gerontic feature.’
    • ‘Scattered undulose presepiments, disrupting as many as ten major septa, present in some adult and all gerontic specimens.’
    • ‘However, this physical process cannot result in the simplification of septal folding in gerontic conchs.’
    • ‘The gerontic whorl of gastropod genera of the subfamily Mitchelliinae is twisted both outwards and backwards, but not upwards as in members of the subfamily Scoliostomatinae.’
    • ‘Specimens of Titanoplina were originally thought to be gerontic representatives of Proplina sibeliusi.’
    • ‘The feature has been considered to be a gerontic characteristic and of no systematic importance.’
    • ‘None of the morphotypes are identical to the forms of A. concentricus and A. tamurai, especially because the latter species has a posterior radial groove and irregular ribs in gerontic individuals.’
    • ‘A permesothyrid foramen is commonly associated with globular, gerontic forms within a single species population.’
    • ‘These differences are not taken to be sufficient to merit recognition of a new species as they may be the result of ecophenotypic variations or gerontic developments in A. gigas.’
    • ‘The new species has also established that the strong revolving internal rib of Endoptygma is not a gerontic character.’
    • ‘A gerontic specimen, more than 8 mm wide, shows the development of high, elevated, bladelike accessory septa.’
    • ‘The gerontic aperture is narrowly elongated in species of Eoscoliostoma, but rather circular in Scoliostoma species.’
    • ‘In summary, examples of deviation from regular tight coiling during late shell stages and the development of a free gerontic whorl may be found in all known Cambrian-Devonian gastropod subclasses.’
    • ‘Rapid growth of the inner and basal parts of the apertural margin during their late shell ontogeny caused twisting of the gerontic whorl both outwards and backwards.’

Origin

Late 19th century: from Greek gerōn, geront- ‘old man’ + -ic.

Pronunciation

gerontic

/jəˈrän(t)ik/