dog's letter

noun

1. the letter r, especially when representing a trill.

Word History and Origins

Origin of dog's letter¹

1585–95; translation of Latin littera canīna, from the resemblance of the sound of the trill to a dog's snarl

Example Sentences

He calls it the "dog's" letter because the trilling of an R was thought to sound like the low growl of a dog.

From Slate