three-screw
three-shaft
three-shift
three-shifted
three-side
three-spindle
three-spool
three-square
three-stage
three-station
  three-step
three-throw
three-tier
three-tiered
three-two-one
three-unit
three-way
three-wire
threshold
thresholded
thresholding

    three-step action

    трёхпозиционное воздействие