one of a pair of crescent-shaped cells that surround a pore (stoma) in the epidermis. Changes in the turgidity of the cells cause the opening and closing of the stoma
guard cell in American English
either of the two bean-shaped cells which surround and control a stoma, or air pore, in the epidermis of a plant
Examples of 'guard cell' in a sentence
guard cell
Diffusion of water from guard cells reverses the process and closes the stoma.