The term "Coming Out" is a shortened form of "coming out of the closet", which is a metaphor for revealing one's sexual orientation and/or transgender status.
Coming Out is the process of recognizing, accepting and sharing with others one's sexual orientation and/or gender identity. Coming out is not a single event, but rather a life-long process. In our society, people tend to assume everyone is heterosexual, so LGBT+ people must continually decide in what situations they want to correct that assumption by disclosing their own orientation or identity. In every new situation, with every new person they meet, they must decide whether or not to come out. There are many stages to coming out, and the process is not the same for everyone. Generally, the coming out process begins with coming out to oneself. This can be stressful at first, because LGBT+ people, like most people, have learned negative stereotypes and misrepresented information about what it means to be LGBT+. Later stages involve coming out to others, such as friends, family, co-workers, etc. It can be a long and difficult process because it not only involves confronting the assumption that everyone is "straight", it also involves confronting discrimination and homophobic and transphobic attitudes along the way. Ultimately, coming out is a freeing experience that allows LGBT+ people to live more authentically, and develop more genuine relationships with others (adapted from HRC.org).