'益虫' literally means 'beneficial insect' — the character 益 (yì) means 'benefit', 'advantage', or 'to benefit', while 虫 (chóng) means 'insect'. Together, they form a compound noun referring to insects that provide ecological or agricultural benefits, such as pollinating crops, preying on pests, or enriching soil. Common examples include ladybugs, bees, lacewings, and earthworms (though technically an annelid, it's often colloquially grouped here).

This term is frequently used in agriculture, ecology, and environmental education to contrast with 害虫 (hài chóng, 'pest'). It carries a positive, protective connotation and appears in scientific outreach, farming guidelines, and nature documentaries. Unlike general terms like 昆虫 (kūnchóng, 'insect'), 益虫 specifically highlights function and human-centered value, making it a context-dependent label rather than a strict biological category.