Definition of decrescent in US English:

decrescent

adjective

  • attributive (of the moon) waning.

    ‘the keen-sighted watcher may catch a glimpse of the slender decrescent moon’
    • ‘The waning moon was "decrescent".’

Origin

Early 17th century: from Latin decrescent- ‘growing less’, from the verb decrescere (see decrease).

Pronunciation

decrescent

/dəˈkres(ə)nt/