Source : Webster's Revised Unabridged Dictionary (1913)

Atones \At*ones\, adv. [See {At one}.] [Obs.]

         Down he fell atones as a stone.          --Chaucer.
Atonic \A*ton"ic\, a. [Cf. F. atonique. See {Atony}.]
   1. (Med.) Characterized by atony, or want of vital energy;
      as, an atonic disease.

   2. (Gram.) Unaccented; as, an atonic syllable.

   3. Destitute of tone vocality; surd. --Rush.

Atonic \A*ton"ic\, n.
   1. (Gram.) A word that has no accent.

   2. An element of speech entirely destitute of vocality, or
      produced by the breath alone; a nonvocal or surd
      consonant; a breathing. --Rush.

   3. (Med.) A remedy capable of allaying organic excitement or
      irritation. --Dunglison.

Source : WordNet®

atonic
     adj 1: characterized by a lack of tonus
     2: used of syllables; "an atonic syllable carries no stress"
        [syn: {unaccented}] [ant: {tonic}]