Trilling \Tril"ling\, n. [Cf. G. drilling.]

1. One of tree children born at the same birth. --Wright.

2. (Crystallog.) A compound crystal, consisting of three individuals.

Source: Webster's Revised Unabridged Dictionary (1913)
 

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.

The sober-suited songstress trills her lay. --Thomson.

Source: Webster's Revised Unabridged Dictionary (1913)