Definition of gerontic in English:

gerontic

adjective

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

    • ‘However, this physical process cannot result in the simplification of septal folding in gerontic conchs.’
    • ‘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.’
    • ‘A few large specimens were known in 1986, however, these were thought to represent gerontic individuals.’
    • ‘The feature has been considered to be a gerontic characteristic and of no systematic importance.’
    • ‘Scattered undulose presepiments, disrupting as many as ten major septa, present in some adult and all gerontic specimens.’
    • ‘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.’
    • ‘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.’
    • ‘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.’
    • ‘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.’
    • ‘Specimens of Titanoplina were originally thought to be gerontic representatives of Proplina sibeliusi.’
    • ‘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.’
    • ‘A permesothyrid foramen is commonly associated with globular, gerontic forms within a single species population.’
    • ‘The new species has also established that the strong revolving internal rib of Endoptygma is not a gerontic character.’
    • ‘The gerontic aperture is narrowly elongated in species of Eoscoliostoma, but rather circular in Scoliostoma species.’
    • ‘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.’
    • ‘A gerontic specimen, more than 8 mm wide, shows the development of high, elevated, bladelike accessory septa.’

Origin

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

Pronunciation:

gerontic

/jəˈrän(t)ik/