n.
A weak chirping sound, as of a young or small bird.
intr.v., tweet·ed, tweet·ing, tweets.
To utter a weak chirping sound.
[Imitative.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.