English Words Starting With O

• optical effects

  plural-nounMedium
  /ˈɒp.tɪ.kəl ɪˈfekts/Visual phenomena, illusions, or changes in appearance created or perceived by manipulating light or the means through which light passes.
• optical fiber

  nounB2
  /ˌɒp.tɪ.kəl ˈfaɪ.bə/A thin, flexible strand of glass or plastic that transmits data as pulses of light, used in telecommunications and networking.
• optical fibre

  nounB2-C1
  /ˌɒp.tɪ.kəl ˈfaɪ.bər/A thin, flexible strand of very pure glass (or sometimes plastic) designed to transmit light signals over long distances with minimal loss of signal strength.
• optical flint

  nounVery Low
  /ˈɒptɪkəl ˈflɪnt/A type of high-quality, very hard glass with high refractive index and dispersion, used for making precision lenses, prisms, and other optical components.
• optical glass

  nounC2
  /ˌɒp.tɪ.kl̩ ˈɡlɑːs/High-quality glass manufactured specifically for its ability to transmit light with minimal distortion, used in lenses and prisms for optical instruments.
• optical illusion

  nounC1
  /ˌɒp.tɪ.kəl ɪˈluː.ʒən/A visually perceived image that is deceptive or misleading, where what the eyes see differs from objective reality.
• optical isomer

  nounLow
  /ˈɒptɪkəl ˈaɪsəmə/One of two or more molecules that are mirror images of each other but cannot be superimposed, differing only in how they rotate plane-polarized light.
• optical isomerism

  nounC1/C2 (Advanced)
  /ˈɒp.tɪ.kəl aɪˈsɒ.mə.rɪ.zəm/A type of stereoisomerism where molecules exist as non-superimposable mirror images of each other, possessing chirality.
• optical mark reading

  nounC2
  /ˈɒp.tɪ.kəl mɑːk ˈriː.dɪŋ/A technology for automatically reading marks (like filled-in bubbles or checkboxes) made on paper forms, typically using an optical scanner.
• optical mouse

  nounMedium
  /ˌɒp.tɪ.kəl ˈmaʊs/A computer pointing device that uses a light-emitting diode (LED) or laser and a digital sensor to detect movement relative to a surface, replacing the older mechanical ball and roller mechanism.
• optical path

  nounLow
  /ˈɒptɪkəl pɑːθ/The path taken by light through an optical system, from the source to a detector or image point, often measured in terms of optical length which includes the effect of the refractive index of the medium.
• optical printer

  nounC2
  /ˈɒp.tɪ.kəl ˈprɪn.tə/A specialised film post-production device used to create composite images, rephotograph film frames, or create visual effects by projecting film through lenses onto a new piece of film.
• optical pumping

  nounRare
  /ˈɒptɪkəl ˈpʌmpɪŋ/A technique in physics where light is used to excite atoms to higher energy states, creating a population inversion necessary for laser operation.
• optical pyrometer

  nounVery Low
  /ˌɒp.tɪ.kəl paɪˈrɒm.ɪ.tər/A device that measures high temperatures by comparing the brightness of an object's incandescence to a calibrated light source.
• optical rotation

  nounC1/C2
  /ˌɒp.tɪ.kəl rəʊˈteɪ.ʃən/The phenomenon where the plane of polarized light is rotated as it passes through certain materials.
• optical scanner

  nounMedium (C1)
  /ˈɒptɪkəl ˈskænə(r)/A hardware device that converts printed text, images, or objects into digital data by using light sensors.
• optical scanning

  nounLow-frequency (Technical/Specialised)
  /ˈɒptɪk(ə)l ˈskænɪŋ/A technology that uses light to capture and digitise images, text, or data from a physical document or object.
• optical sound

  nounC2 / Very Low Frequency
  /ˈɒp.tɪ.kəl saʊnd/A method of recording and reproducing sound for film where the audio signal is encoded as a visible waveform directly onto the film strip, alongside the images.
• optical soundtrack

  nounC2/Technical
  /ˌɒp.tɪ.kəl ˈsaʊnd.træk/A method of recording and reproducing sound for film, where the audio signal is stored as a visible pattern of light and dark areas alongside the film frames, which is then read by a photoelectric cell.
• optical tooling

  nounVery Low
  /ˈɒp.tɪ.kəl ˈtuː.lɪŋ/A precise measurement and alignment technique using optical instruments (like theodolites, alignment telescopes, or lasers) to position, align, or inspect machinery, structures, or components in engineering and manufacturing.

Showing 1581–1600 of 3187 words.