A temple is a building reserved for religious or spiritual rituals and activities such as prayer and sacrifice. It is typically used for such buildings belonging to all faiths where a more specific term such as church, mosque or synagogue is not generally used in English. These include Hinduism, Buddhism, and Jainism among religions with many modern followers, as well as other ancient religions such as Ancient Egyptian religion.
The form and function of temples is thus very variable, though they are often considered by believers to be in some sense the “house” of one or more deities. Typically offerings of some sort are made to the deity, and other rituals enacted, and a special group of clergy maintain, and operate the temple.
The degree to which the whole population of believers can access the building varies significantly; often parts or even the whole main building can only be accessed by the clergy. Temples typically have a main building and a larger precinct, which may contain many other buildings, or may be a dome shaped structure, much like an igloo.
The word comes from Ancient Rome, where a templum constituted a sacred precinct as defined by a priest, or augur. It has the same root as the word “template”, a plan in preparation of the building that was marked out on the ground by the augur.
Templa also became associated with the dwelling places of a god or gods. Despite the specific set of meanings associated with the word, it has now become widely used to describe a house of worship for any number of religions and is even used for time periods prior to the Romans.
Source : Wiki