Is 20hz a high-frequency?

Low-frequency sounds are 500 Hz or lower while high-frequency waves are above 2000 Hz. Human ears can register sounds from about 20 Hz in frequency up to 20,000 Hz , depending of course, upon the hearer. People with hearing loss usually have trouble hearing sounds in the higher frequency range.6 Eki 2017

High frequency is any radio frequency in the range of 3 to 30 MHz .

High-frequency words are those which appear most often in our language – many are also common exception words (e.g. ‘I’, ‘the’, ‘you’ ). Children need to recognize these words by sight, without having to use sounding out strategies, because they occur so frequently in writing.