Definition of aggrade in English:

aggrade

Pronunciation /əˈɡreɪd/

verb

Geography
  • Of a river, current, or other agency: to build up (a valley, plain, etc.) by deposition of detrital material. Contrasted with "degrade".

Origin

Late 19th century. From classical Latin ag-, variant (before g) of ad- ad- + grade, after degrade.