illegal
illuminance
illuminant
illuminate
illuminated-indicator
illuminating
illumination
illuminator
illuminometer
IM
  image
image-converter
image-dissector
image-force
image-forming
image-frequency
image-intensifier
image-interference
image-processing
imager
image-rejection

    image phase coefficient

    характеристическая постоянная распространения (несимметричного четырёхполюсника)