Explain the terminology Niche ?

The term niche is used often in ecology, and its meaning has been defined and interpreted in various ways over the years. An organisms niche has been equated to the organisms habitat, its functional role, its food habits, and where an organism lives and what it does within the context of an ecosystem. Although complex, you do need to understand that the concept of niche is very important to understanding ecology.

An organisms niche can be thought of as the sum total of where it lives and how it functions in space and time. In other words, a niche also reflects how an organism interacts with its environment in every way. Defining the niche of an organism might require knowing things like specifically what it eats, how it eats, when it eats (time of day and season), what predators and decomposers feed on it, where it spends its time (if in the water, what part of the water column and how long and how often in each part, how it alters its physical and biological environment, and also things like what types of parasites it hosts.