1. Any stratum or layer lying underneath another
   "The substratum of the aquarium was covered with fine gravel";
   - substrate
    
2. A surface on which an organism grows or is attached
   "the gardener talked about the proper substratum for acid-loving plants";
   - substrate
    
3. An indigenous language that contributes features to the language of an invading people who impose their language on the indigenous population
   "the Celtic languages of Britain are a substratum for English";
   - substrate

Derived forms: substrata

Type of: indigenous language, stratum, surface

Encyclopedia: Substratum