AIESEC. An international not-for-profit organization that provides students with leadership training and internship opportunities at for-profit and not for profit organizations. AIESEC, comes from the French acronym for Association internationale des étudiants en sciences économiques et commerciales. As of January 2014, the AIESEC network includes over 90,000 members in 124 countries and territories. It is the largest student-run organization in the world.