Guilherme, also known as William, is a common name in Portuguese-speaking countries. It is derived from the Germanic name Wilhelm, which means "resolute protector." The name is often associated with various historical figures and has been popular in literature and culture. In modern times, Guilherme is frequently used in Brazil and Portugal. It can be found in various professions, including sports, arts, and business. Notable individuals with this name include Guilherme de Almeida, a Brazilian poet, and Guilherme Boulos, a prominent political activist.