[dez-mid] 
| any single-celled freshwater algae of the family Desmidiaceae, characterized by a division of the body into mirror-image halves joined by a bridge containing the nucleus, and having a spiny or bristly exterior: sometimes forming into colonies or branching filaments. |
| des·mid (děs'mĭd) n. Any of various green unicellular freshwater algae of the family Desmidiaceae, often forming chainlike colonies. [From New Latin Desmidiāceae, family name, from Desmidium, type genus, from Greek desmos, bond, from dein, to bind.] |