An instance or act of undulating. / A wavy appearance or outline; waviness. / (music) A tremulous tone produced by a peculiar pressure of the finger on a string.

plural of undulation

(physics) A periodic structure of dipole magnets that generates a low-energy collimated beam of radiation.

plural of undulator

Not dulled; sharp or alert.

(obsolete) undulating

undulatory

present participle of undull

Not dull; sharp.

(transitive) To remove the dullness of; clear.