An Imam is an Islamic leader. For Sunni Muslims, an “Imam” is a prayer leader of a mosque. In this context, Imams may lead Islamic prayers, serve as community leaders, and provide religious guidance. For Sunnis, anyone can study the basic Islamic sciences and become an Imam.
Shia Muslims reserve the word “Imam” for the leaders of the entire Islamic community. These Imams trace their family back to the Prophet Muhammad and are considered infallible (incapable of error).
Text adapted from English Wikipedia, Creative Commons Attribution-ShareAlike License 4.0.