1. small spiny sea creatures with round shells
Usage: marine biology
2. mischievous or raggedly dressed children
Usage: informal; sometimes dated

Examples

• The tide pools were filled with colorful sea urchins.
• Divers must be careful not to step on the sharp spines of urchins.
• The street urchins played games in the alley.
• A group of little urchins ran through the marketplace.
• Sea urchins are important members of the ocean ecosystem.
• The children looked like proper little urchins after playing in the mud.