ADVERB (2)

1. at full speed; with great haste;
- Example: "the children ran down the hill amain"

2. with all your strength;
- Example: "he pulled the ropes amain"

The Collaborative International Dictionary of English v.0.48:

Amain \A*main"\, adv. [Pref. a- + main. See 2d Main, n.]
   1. With might; with full force; vigorously; violently;
      exceedingly.
      [1913 Webster]

            They on the hill, which were not yet come to blows,
            perceiving the fewness of their enemies, came down
            amain.                                --Milton.
      [1913 Webster]

            That striping giant, ill-bred and scoffing, shouts
            amain.                                --T. Parker.
      [1913 Webster]

   2. At full speed; in great haste; also, at once. "They fled
      amain." --Holinshed.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Amain \A*main"\, v. t. [F. amener. See Amenable.] (Naut.)
   To lower, as a sail, a yard, etc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

amain \a*main"\, v. i. (Naut.)
   To lower the topsail, in token of surrender; to yield.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amain
    adv 1: at full speed; with great haste; "the children ran down
           the hill amain"
    2: with all your strength; "he pulled the ropes amain"