say it: tril
trill is a noun and verb meaning "a note that alternates rapidly with another note a semitone above it". It carries 4 recorded senses.
the articulation of a consonant (especially the consonant `r') with a rapid flutter of the tongue against the palate or uvula
“he pronounced his R's with a distinct trill”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for trill come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.