rockerとは何ですか?One that rocks, as:A rocking chair.A rocking horse.One of the two curved pieces upon which a cradle, rocking chair, or similar device rocks.A cradle used for washing or panning ores.A small curved blade with a toothed edge used in mezzotint engraving to roughen the surface of the metal plate.An object having a curved form, as the keel of a ship or a skate blade sharpened in a curve.A curved stripe at the bottom part of a chevron worn by noncommissioned officers above the rank of sergeant.Music A rock 'n' roll song, singer, or musician.Music A fan of rock 'n' roll.off (one's) rocker Slang Out of one's mind; crazy.