Source : Webster's Revised Unabridged Dictionary (1913)

Immediately \Im*me"di*ate*ly\, adv.
   1. In an immediate manner; without intervention of any other
      person or thing; proximately; directly; -- opposed to
      {mediately}; as, immediately contiguous.

            God's acceptance of it either immediately by
            himself, or mediately by the hands of the bishop.
                                                  --South.

   2. Without interval of time; without delay; promptly;
      instantly; at once.

            And Jesus . . . touched him, saying, I will; be thou
            clean. And immediately his leprosy was cleansed.
                                                  --Matt. viii.
                                                  3.

   3. As soon as. Cf. {Directly}, 8, Note.

   Syn: Directly; instantly; quickly; forthwith; straightway;
        presently. See {Directly}.

Source : WordNet®

immediately
     adv 1: without delay or hesitation; with no time intervening; "he
            answered immediately"; "found an answer straightaway";
            "an official accused of dishonesty should be suspended
            forthwith"; "Come here now!" [syn: {instantly}, {straightaway},
             {straight off}, {directly}, {now}, {right away}, {at
            once}, {forthwith}, {in real time}, {like a shot}]
     2: near or close by; "he passed immediately behind her"
     3: bearing an immediate relation; "this immediately concerns
        your future"