trill, in music, ornament consisting of the more or less rapid alternation of two adjacent notes. Indicated by any of several conventional symbols, it varies in speed and duration and in the manner of its beginning and ending according to context. Originating in the Renaissance, the trill became the most important of ornaments during the baroque period. In British usage the term shake is more common.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.