1. the caterpillar larva of a geometrid moth that moves by arching its body and bringing its rear end forward to meet its front end

Examples

• The spanworm inched its way across the leaf.
• Children watched the green spanworm loop along the branch.
• The spanworm’s distinctive movement makes it easy to identify.
• Gardeners often find spanworms feeding on their plants.
• The spanworm arched its body as it moved forward.
• A small spanworm dropped from the tree on a silk thread.