English Words Starting With O

• optic

  adjectivenounB2
  /ˈɒptɪk/Relating to the eye or vision; pertaining to the science of light and vision.
• optic axis

  nounC2
  /ˌɒp.tɪk ˈæk.sɪs/In optics and crystallography, the direction in a crystal or optical system along which light propagates without experiencing double refraction or birefringence.
• optic chiasma

  nounVery Low
  /ˌɒp.tɪk kaɪˈæz.mə/The X-shaped structure at the base of the brain where the two optic nerves partially cross.
• optic disc

  nounC1
  /ˈɒp.tɪk ˌdɪsk/The circular area at the back of the inner eye where the optic nerve connects to the retina; it lacks photoreceptors, creating a blind spot.
• optic nerve

  nounC2
  /ˌɒp.tɪk ˈnɜːv/The nerve that transmits visual information from the retina to the brain.
• optic thalamus

  nounVery Low / Obsolete Technical
  /ˌɒp.tɪk ˈθæl.ə.məs/An obsolete neuroanatomical term for the thalamus, a brain structure that relays sensory signals (including visual information) to the cerebral cortex.
• optical

  adjectivenounB2
  /ˈɒptɪk(ə)l/Relating to vision, light, or the science of optics.
• optical activity

  nounLow
  /ˈɒptɪkl ækˈtɪvəti/The property of certain substances to rotate the plane of polarisation of plane-polarised light passing through them.
• optical art

  nounLow
  /ˌɒp.tɪ.kəl ˈɑːt/A style of abstract art that uses geometric patterns to create illusions of movement, vibration, or three-dimensional depth.
• optical astronomy

  nounC1-C2
  /ˌɒp.tɪ.kəl əˈstrɒn.ə.mi/The branch of astronomy that observes celestial objects using visible light.
• optical bench

  nounC2
  /ˈɒp.tɪ.kəl bentʃ/A long, rigid, horizontal table or rail used in laboratories to hold and precisely align optical components (like lenses, mirrors, light sources) for experiments in optics.
• optical center

  nounC2
  /ˈɒptɪkəl ˈsɛntə/The point on a lens where light passes through without deviation; the point in an eyeglass prescription aligned with the center of the pupil.
• optical character reader

  nounC1
  /ˈɒptɪkəl ˈkærəktə ˈriːdə/A hardware device or system that scans printed text and converts it into digital data using optical character recognition (OCR) technology.
• optical character recognition

  nounLow
  /ˌɒp.tɪ.kəl ˈkæ.rɪk.tə ˌrek.əɡˈnɪʃ.ən/The technology that enables computers to identify and convert images of typed or handwritten text into machine-encoded text.
• optical computer

  nounC1/C2
  /ˈɒp.tɪ.kəl kəmˈpjuː.tə(r)/A theoretical or experimental computing device that uses photons (light) instead of electrons to process information.
• optical crown

  nounC2 (Very low frequency, highly specialized)
  /ˌɒp.tɪ.kəl ˈkraʊn/A type of high-quality, low-dispersion glass (crown glass) used in lenses and optical instruments.
• optical density

  nounTechnical/Scientific
  /ˌɒp.tɪ.kəl ˈden.sə.ti/A scientific measurement of how much a material reduces the intensity of light passing through it; a logarithmic measure of the proportion of light absorbed or scattered.
• optical disc

  nounMedium
  /ˌɒp.tɪ.kəl ˈdɪsk/A flat, circular data storage medium from which data is read and written using a laser.
• optical disk

  nounB2
  /ˌɒp.tɪ.kəl ˈdɪsk/A storage medium for digital data, written to and read from using laser light.
• optical double star

  nounVery low
  /ˈɒp.tɪ.kəl ˈdʌb.əl stɑː/Two stars that appear close together in the sky due to their line of sight from Earth, but are not gravitationally bound.

Showing 1561–1580 of 3187 words.