What term describes the filter circuit's ability to distinguish between high and low frequencies?

The term that best describes the filter circuit's ability to distinguish between high and low frequencies is discrimination. Discrimination refers to the capability of a filter to differentiate between various frequency components of a signal, allowing it to selectively respond to certain frequencies while attenuating others. This is particularly crucial in signal processing where you might want to isolate a specific frequency band, such as keeping only audio frequencies while ignoring RF signals.

In filter design, effective discrimination improves the performance of the system by reducing the noise and unwanted signals that can interfere with the desired output. This is important in various applications including communications and audio processing, where clarity and precision in frequency selection are paramount.