Definition of "trill" [trill]

• A fluttering or tremulous sound, as that made by certain birds; a warble. (noun)
• Music The rapid alternation of two tones either a whole or a half tone apart. (noun)
• Music A vibrato. (noun)
• Linguistics A rapid vibration of one speech organ against another, as of the tongue against the alveolar ridge in Spanish rr. (noun)
• Linguistics A speech sound pronounced with such a vibration. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Most painful to me, however, is that the trill, which is so important to the understanding of the sonata's main theme, is to be played fortissimo, while elsewhere in the movement remaining remote and mysterious."
• "The trill is the most difficult of all vocal exercises."
• "There still remains the trill, which is best practised in the beginning as follows: --"