Why Frequency counts how many complete cycles an alternating waveform goes through each second, and that unit is the hertz (Hz), named for Heinrich Hertz. One hertz is one cycle per second, so a 7.1 MHz signal reverses direction 7,100,000 full cycles every second.
Watch out The henry is the unit of inductance and the farad is the unit of capacitance, both component properties rather than a rate; "epicycles per second" is not a real unit at all.
Hertz = cycles per second. Henry = inductance, Farad = capacitance.