In relation to square waves, which term indicates that the waveform must be perfectly square?

The term that indicates the waveform must be perfectly square is "Pure." In the context of square waves, a "pure" waveform is one that has no distortion or deviation from the ideal square shape, exhibiting sharp transitions between the high and low states without any rounded edges or variations in amplitude. The characteristics of a pure square wave include an instantaneous rise and fall time, equal duration of the high and low states (50% duty cycle), and no harmonic distortion, which ensures the waveform maintains its integrity as it represents a perfect square.

Other terms, while closely related, do not convey the same precise requirements as "pure." For example, "perfect" may imply an ideal condition but does not strictly denote the absence of distortion. "Ideal" often refers to theoretical constructs rather than practical reality, where real-world imperfections may still exist. "Accurate" implies closeness to a desired value but does not address the specific shape or characteristics of the waveform itself. Thus, "pure" is the most appropriate term when describing a waveform that must be perfectly square.