A prefix signifying in or into, used in many English words,
   chiefly those borrowed from the French. Some English words are written
   indifferently with en-or in-. For ease of pronunciation it is commonly
   changed to em-before p, b, and m, as in employ, embody, emmew. It is
   sometimes used to give a causal force, as in enable, enfeeble, to cause
   to be, or to make, able, or feeble; and sometimes merely gives an
   intensive force, as in enchasten. See In-.