situated or occurring below the crust of the earth
Word origin
[1895–1900; sub- + crustal]This word is first recorded in the period 1895–1900. Other words that entered Englishat around the same time include: Marxism, apothecaries' measure, flamenco, freewheel, neonsub- is a prefix occurring originally in loanwords from Latin (subject; subtract; subvert; subsidy). On this model, sub- is freely attached to elements of any origin and used with the meaning “under,” “below,”“beneath” (subalpine; substratum), “slightly,” “imperfectly,” “nearly” (subcolumnar; subtropical), “secondary,” “subordinate” (subcommittee; subplot)