Breadcrumb Home > Dictionary > Index S spiral arm: Meaning and Definition of Find definitions for: spi'ral arm' Pronunciation: [key] — Astron. Astron. any of the elongated and curved spiral sections that are connected to the center of a spiral galaxy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spiral spiral bevel gear TrendingHere are the facts and trivia that people are buzzing about. Did Birds Evolve from Dinosaurs? The Twelve Dancing Princesses Current Events This Week: January 2023 African Americans by the Numbers Andersen's Fairy Tales: Contents The Celtic Twilight: A Teller of Tales ✖ Related Content Daily Word Quiz: hubris Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language