Origin

This character combines a person marker on the left with a sound component on the right. The left part, a small version of the character for person, signals that this term relates to people. The right part, pronounced similar to "gu," provides the sound hint for how to say the character. Over time, the meaning shifted from the original sense to encompassing ideas of pairing or meeting by chance—perhaps because two people meeting accidentally can be thought of as a "couple" or pair. The abstract notion of "even number" likely developed from the sense of things coming in matching pairs.