A rapid alternation between a written note and the one above it in music

• Usually marked tr in notation

A consonant produced by rapid repeated contact at the place of articulation

• As in the Spanish rr sound

A short, high, warbling cat sound used in friendly greeting

To produce a trill in singing or on an instrument

• To roll the r sound
• To quaver or sound with rapid vibrations

Authentic and respected; truly real (slang)