Definition of ecdysis in English:


Pronunciation /ɛkˈdʌɪsɪs//ˈɛkdɪsɪs/


mass nounZoology
  • The process of shedding the old skin (in reptiles) or casting off the outer cuticle (in insects and other arthropods).

    • ‘During terminal pleateau there are a series of large pulses of circulating ecdysteroids which appear to be necessary for successful ecdysis of the entire exoskeleton.’
    • ‘In both groups, tissue loss must occur before a critical period to permit regeneration before the next ecdysis and proecdysial processes are suspended during regeneration in order to maintain proper timing of events.’
    • ‘Considering Crustacea as an analogy, abnormal secretion of exuviation hormones in trilobite exoskeletons could also have caused irregular ecdysis and given rise to aberrant exoskeletal morphology.’
    • ‘Upon ecdysis, a chitinous duplicature of the exoskeleton is shed and a growth band is added to the valves.’
    • ‘At ecdysis, the animal sheds the old exoskeleton while absorbing large quantities of water to stretch the new exoskeleton.’


Mid 19th century: from Greek ekdusis, from ekduein ‘put off’, from ek- ‘out, off’ + duein ‘put’.