[1760–70; sub- + axillary]This word is first recorded in the period 1760–70. Other words that entered Englishat around the same time include: boutique, broadcast, letdown, provincialism, sounding boardsub- 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)