What does an increase of one octave represent in terms of frequency?

An increase of one octave in terms of frequency signifies a doubling of frequency. The concept of an octave is rooted in music theory and acoustics, where an octave is defined as the interval between one frequency and another frequency that is double or half of it. For example, if you have a note at 440 Hz (which is the standard tuning pitch for musical A), moving up one octave would bring you to 880 Hz. This doubling means that octaves are fundamental in understanding pitch relationships, and they illustrate how human perception of sound frequency is logarithmic rather than linear. Therefore, the correct answer reflects the essential nature of how sound frequencies relate to one another within this framework.