bakˈtirēəm, -tēr- noun
Etymology: New Latin, from Greek baktērion small staff, diminutive of baktēria staff; akin to Latin baculum staff, Greek baktron stick
1. capitalized , in some classifications : a more or less inclusive genus comprising straight rod-shaped bacteria with no flagella and (in modern usage) no spores and including a variable assemblage of species most of which are more commonly placed in other genera — compare acetobacter , aerobacter , alcaligenes
2. plural bacte·ria -rēə : any of a large group of microscopic plants constituting the class Schizomycetes, having round, rodlike, spiral, or filamentous single-celled or noncellular bodies that are often aggregated into colonies, are enclosed by a cell wall or membrane, usually lack fully differentiated nuclei, and are often motile by means of flagella, reproducing by fission, by the formation of asexual resting spores or, in some higher forms, by conidia or by imperfectly understood sexual processes, living in soil, water, organic matter or the live bodies of plants and animals, and being autotrophic, saprophytic, or parasitic in nutrition and important to man because of their chemical effects (as in nitrogen fixation, putrefaction, and various fermentations) and as pathogens
Synonyms: see microorganism