from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A phrase that is deliberately designed to be difficult to say correctly, usually because of varying combinations of similar phonemes.
from The Century Dictionary and Cyclopedia
- n. A sentence or verse constructed with a view to test the enunciation or dexterity of a speaker. The following is an example: Theophilus Thistle, thistle-sifter, sifted a sieveful of unsifted thistles, etc.
tongue + twister (Wiktionary)