En- definition, a prefix occurring originally in loanwords from French and productive in English on this model, forming verbs with the general sense “to cause (a person or thing) to be in” the place, condition, or state named by the stem; more specifically, “to confine in or place on” (enshrine; enthrone; entomb); “to cause to be in” (enslave; entrust; enrich; encourage; endear); “to restrict” in the manner named by the stem, typically with the additional sense “on all ...