Bacteria:

Unicellular organism of simple structure, which is found in soil, water, or as a parasite or saprophyte in animals and plants.

Bactericidal:

A substance that kills bacteria.

Bacteriostatic:

A substance that inhibits the growth of bacteria but not kill them simply stops growing.

Balsam:

Healing or calming drug substance.

Biennial plant:

The one that lives for two successive growing season.

Bile:

Substance secreted by the liver, is stored in the gall bladder and then passes into the duodenum via the bile duct. It contains lecithin, cholesterol, salts and pigments, among other substances.

Bilirubin:

Red bile pigment, being a breakdown product of hemoglobin.

Biosphere:

Part of the globe where there are living organisms.

Bract:

Sheet opposite the flower, and that is usually found at the base of the stalk. Modified leaf whose axial is a flower.

Bryophytes:

Main Division of the plant kingdom where mosses are included.

Bulb:

Specialized reproductive organ, Subway, consisting of a short stalk with a fleshy leaf bases swollen.