What is the meaning of extrusion?

noun

• Something that bulges out or is protuberant or projects from its surroundings.
  • usage: "the gun in his pocket made an obvious bulge"; "the hump of a camel"; "he stood on the rocky prominence"; "the occipital protuberance was well developed"; "the bony excrescence between its horns"
  • synonyms: bulge, bump, hump, swelling, gibbosity, gibbousness, jut, prominence, protuberance, protrusion, excrescence
• Squeezing out by applying pressure.
  • usage: "an unexpected extrusion of toothpaste from the bottom of the tube"; "the expulsion of pus from the pimple"
  • synonyms: expulsion