Amateur theatre, also known as amateur dramatics, is theatre performed by amateur actors and singers. Amateur theatre groups may stage plays, revues, musicals, light opera, pantomime or variety shows, and do so for the social activity as well as for aesthetic values. Productions may take place in venues ranging from the open air, community centres, or schools to independent or major professional theatres. Amateur theatre is distinct from the professional or community theatre because performers are usually not paid. Amateur actors are not typically members of actors' unions. Opinions vary on how to define "amateur" in relation to theatre. Technically speaking, an "amateur" is anyone who does not accept, or is not offered, money for their services. One interpretation of this is: "One lacking the skill of a professional, as in an art". Another is: "A person who engages in an art, science, study, or athletic activity as a pastime rather than as a profession". An amateur actor is unlikely to be a member of an actors' union as most countries' trades unions have strict policies in place. In the United States, the Actors' Equity Association serves a similar purpose: to protect the professional industry and its artists. While the majority of professional stage performers have developed their skills and studied their craft at recognised training institutions such as the Royal Academy of Dramatic Art (London), Juilliard School (New York) or National Institute of Dramatic Art (Sydney), amateurs are not usually professionally trained. Amateur theatre (amateur dramatics) can be defined as "theatre performances in which the people involved are not paid but take part for their own enjoyment". Locally organised theatrical events provide a source of entertainment for the community, and can be a fun and exciting hobby, with strong bonds of friendship formed through participation. Many amateur theatre groups reject the "amateur" label and its negative association with "amateurish", preferring to style themselves "dramatic societies", "theatre groups" or just "players".