APA Dictionary of Psychology

pl. n. (sing. labium) four lip-shaped folds of tissue forming part of the female external genitalia (see vulva). The labia—comprising a larger, outer pair, the labia majora (sing. labium majus), and a thinner, inner pair, the labia minora (sing. labium minus)—enclose the clitoris and the openings of the urethra and vagina.