1. The outermost protective layer or covering of a spore, especially in bacteria and fungi.
Usage: technical; biology

Examples

• The exosporium of bacterial spores provides resistance to harsh environmental conditions.
• Scientists examined the exosporium under an electron microscope to study its structure.
• The exosporium acts as a barrier against chemical and physical damage.
• In Bacillus species, the exosporium is composed of protein and carbohydrate layers.
• The integrity of the exosporium is crucial for spore survival and dispersal.