free-field
free-free
free-hole
free-ion
free-line
freely
free-motional
free-point
free-radical
free-running
  free-space
freeway
freeze
freeze-out
freezing
freezing-out
Frenkel
Frenkel-Poole
frequency
frequency-agile
frequency-agility

    free-space characteristic impedance

    волновое сопротивление свободного пространства