biodegradability - decomposition?

"Biodegradability" means the ability to be decomposed by micro-organisms.

"Decomposition" means the process of being broken down by micro-organisms.

"Biodegradation" means the same as "decomposition". If something is biodegradable then it is possible for bacteria, especially in the soil, to break it down.

A "biodegradable" product has the ability to break down, safely and relatively quickly, by biological means, into the raw materials of nature and disappear into the environment. These products can be solids biodegrading into the soil (which we also refer to as compostable), or liquids biodegrading into water. Biodegradable plastic is intended to break up when exposed to microorganisms (a natural ingredient such as cornstarch or vegetable oil is added to achieve this result).

Yep, pretty much the same thing. "Biodegradable" is usually used when one talks about food or about refuse items, whereas "decomposition" is more often used when talked about living things after they expire. At least, that's how I've heard it.

Regarding the difference between "biodegradability" and "decomposition", the word biodegradable is an adjective, whereas the word decomposition is a noun.

Lab example: In melting point determinations, some samples "decompose" without ever melting. In this case no organisms are involved--just thermal energy and oxygen. A synonym for decomposition in this situation could be degradation (not biodegradation).