The Collaborative International Dictionary of English v.0.48:

Trilling \Tril"ling\, n. [Cf. G. drilling.]
   1. One of tree children born at the same birth. --Wright.
      [1913 Webster]

   2. (Crystallog.) A compound crystal, consisting of three
      individuals.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Trill \Trill\, v. t. [imp. & p. p. Trilled; p. pr. & vb. n.
   Trilling.] [It. trillare; probably of imitative origin.]
   To impart the quality of a trill to; to utter as, or with, a
   trill; as, to trill the r; to trill a note.
   [1913 Webster]

         The sober-suited songstress trills her lay. --Thomson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Trilling
    n 1: United States literary critic (1905-1975) [syn: Trilling,
         Lionel Trilling]