Definition of "rocker"

rocker

/ˈɹɒk.ə(ɹ)/

noun
plural rockers
1. A curved piece of wood attached to the bottom of a rocking chair or cradle that enables it to rock back and forth.
  Quotations
  The cradle-rockers had done hard duty for so many years, under the weight of so many children, on that flagstone floor, that they were worn nearly flat, in consequence of which a huge jerk accompanied each swing of the cot, flinging the baby from side to side like a weaver's shuttle, as Mrs Durbeyfield, excited by her song, trod the rocker with all the spring that was left in her after a long day's seething in the suds.
  1891, Thomas Hardy, Tess of the d'Urbervilles, volume 1, London: James R. Osgood, McIlvaine and Co., page 30
2. A rocking chair.
  Quotations
  A few days before he turned 80He was sittin' out back in a rocker
  2021, “Buy Dirt”, in Buy Dirt, performed by Jordan Davis
3. (surfing) The lengthwise curvature of a surfboard. (More rocker is a more curved board.)
4. The breve below as in ḫ.
  Quotations
  Like the editors of other Elamite texts, I omit the diacritic rocker from h in Elamite and from H in logograms in Elamite texts. I retain the rocker in ḫ and Ḫ in Sumerian and Akkadian.
  1984, Matthew Wolfgang Stolper, Texts from Tall-i Malyan Elamite Administrative Texts (1972–1974) (Occasional Publications of the Babylonian Fund; 6), University of Pennsylvania Press, page XVII
  Although the exact sound value of s remains uncertain, and there is only one such sibiliant in Hittite, it is traditionally transliterated with a so-called haček: š. This should not be taken, however, as evidence that it was a palatal sound (as sh in show). The same is true for the traditional “rocker” under the laryngeal ḫ: there is no other h-sign, and the diacritic is not strictly necessary.
  2011, Theo van den Hout, The Elements of Hittite, Cambridge University Press, page 13
  Semitistic transliteration systems […] a number of features are common to most of them: […] ḫ (“h” with a “rocker,” conventionally called “hooked h”) for the voiceless velar/uvular fricative, IPA [x]/[χ], […]
  2019, John Huehnergard, “Proto-Semitic”, in Huehnergard, John and Na'ama Pat-El, editors, The Semitic Languages, 2nd edition, Routledge, page 15
5. Someone passionate about rock music.
6. A musician who plays rock music.
7. (informal) A rock music song.
  Quotations
  "Girls & Boys" is […] also a tart, sneering rocker, full of ingenious musical gestures […]
  September 2010, Pitchfork Media, The Top 200 Tracks of the 1990s
8. One who rocks something.
  Quotations
  It was I, sir, said the rocker, who had the honour, some thirty years since, to attend on your highness in your infancy.
  1645, Thomas Fuller, Good Thoughts in Bad Times
9. (UK) A member of a British subculture of the 1960s, opposed to the mods, who dressed in black leather and were interested in 1950s music.
10. Any implement or machine working with a rocking motion, such as a trough mounted on rockers for separating gold dust from gravel, etc., by agitation in water.
11. A tool with small teeth that roughens a metal plate to produce tonality in mezzotints.
12. A rocking horse.
13. A rocker board.
14. A skate with a curved blade, somewhat resembling in shape the rocker of a cradle.
15. A kind of electrical switch with a spring-loaded actuator.
16. (engineering) A rock shaft.
17. (military) A curved line accompanying the chevrons that denote rank, qualifying the rank with a grade.
  Quotations
  Cadet Sergeant First Class: 3 Chevrons and 2 rockers. Cadet Master Sergeant: 3 Chevrons and 3 rockers. Cadet First Sergeant: 3 Chevrons, 3 rockers with a diamond inset.
  2000, Mark Collantes, The Academy, page 66