The Collaborative International Dictionary of English v.0.48:

Lentor \Len"tor\ (-t[o^]r), n. [L., fr. lentus pliant, tough,
   slow. See Lent, a.]
   1. Tenacity; viscidity, as of fluids.
      [1913 Webster]

   2. Slowness; delay; sluggishness. --Arbuthnot.
      [1913 Webster]