In the olden days we used to say c/s or cps (cycles per second). I think it was sometime in the late 60s when it was decided by some august deliberative body to change cps to Hertz (Hz) to recognize Heinrich Hertz's contribution to physics and radio.

"The SI unit hertz (Hz) was established in his honor by the IEC in 1930 for frequency, an expression of the number of times that a repeated event occurs per second. It was adopted by the CGPM (Conférence générale des poids et mesures) in 1960, officially replacing the previous name, "cycles per second" (cps)."