The Collaborative International Dictionary of English v.0.48:

Vow \Vow\, v. t. [imp. & p. p. Vowed; p. pr. & vb. n.
   Vowing.] [OE. vouen, OF. vouer, voer, F. vouer, LL. votare.
   See Vow, n.]
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   1. To give, consecrate, or dedicate to God, or to some deity,
      by a solemn promise; to devote; to promise solemnly. "When
      thou vowest a vow unto God, defer not to pay it." --Eccl.
      v. 4.
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            [Men] that vow a long and weary pilgrimage. --Shak.
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   2. To assert solemnly; to asseverate.
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