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-.-a prefix from gr. / in, meaning in; as, encephalon, entomology. see in-.