峨嵋 derives from the word 蛾眉 (the feathery feelers of a moth), so named because the peaks of Mount Emei do in fact resemble the feelers of a moth (see pictures). The "insect" radical (虫) on the left side of the first character 蛾 was later replaced with the "mountain" radical (山). Thus, 蛾 eventually became 峨, so as to denote the mountain. The "mountain" radical can be optionally added to the second character 眉. Both 峨嵋 and 峨眉 have been used through the centuries.