The Collaborative International Dictionary of English v.0.48:

Truelove \True"love`\, n.
   1. One really beloved.
      [1913 Webster]

   2. (Bot.) A plant. See Paris.
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   3. An unexplained word occurring in Chaucer, meaning,
      perhaps, an aromatic sweetmeat for sweetening the breath.
      --T. R. Lounsbury.
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            Under his tongue a truelove he bore.  --Chaucer.
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   Truelove knot, a complicated, involved knot that does not
      readily untie; the emblem of interwoven affection or
      engagement; -- called also true-lover's knot.
      [1913 Webster]

WordNet (r) 3.0 (2006):

truelove knot
    n 1: a knot for tying the ends of two lines together [syn:
         fisherman's knot, true lover's knot, truelove knot]