plural of urchin

A mischievous child. / A street urchin, a child who lives, or spends most of their time, in the streets. / A sea urchin.

plural of sea urchin

(Britain, obsolescent) A child who lives, or spends most of his or her time, in the streets; sometimes a petty thief or pickpocket.

Any of many marine echinoderms, of the class Echinoidea, commonly found in shallow water, having a complex chewing structure named Aristotle's lantern.

(chemistry) A dense cluster of nanotubes having a form resembling a sea urchin, especially one made from vanadium oxides.

Any of numerous clypeastroid sea urchins (sand dollars) of the genera Melitta, Rotula and Encope, with one or more perforations resembling keyholes.

Any sea urchin of the genus Rotula having a round, flat shell; a type of sand dollar.

plural of heart urchin

Any echinoderm of the class Spatangoida.