The Collaborative International Dictionary of English v.0.48:

Approximate \Ap*prox"i*mate\, a. [L. approximatus, p. p. of
   approximare to approach; ad + proximare to come near. See
   Proximate.]
   1. Approaching; proximate; nearly resembling.
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   2. Near correctness; nearly exact; not perfectly accurate;
      as, approximate results or values.
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   Approximate quantities (Math.), those which are nearly, but
      not, equal.
      [1913 Webster]