The term arc may refer to the following:

  • Arc (activity-regulated cystoskeleton-associated protein, also Arg3.1), a type of protein and a member of the immediate-early gene family that is considered important in neurobiology
  • Arc (Anoxic Respiratory Control) system, a type of two-component system hemoprotein that regulates various genes
  • a closed segment of a differentiable curve in Euclidean geometry
  • a set of points in finite projective geometry that satisfies a feature of curved figures in continuous geometries in an intuitive way
  • arcminute (also minute of arc, MOA, arcminute, arcmin, minute arc), a unit of measurement equal to 1?60 of a degree
  • arc (or arch), a type of curved structure that spans a space, but may or may not support weight above it