foundry
four
four-arm
four-bay
four-capsule
four-channel
four-course
four-electrode
four-frequency
four-horn
  Fourier
Fourier-transform
four-layer
four-level
four-of-eight
four-out-of-eight
four-output
four-over-four
four-phase
four-point
four-pole

    Fourier analysis

    гармонический анализ