Guru Granth Sahib: This is the central religious scripture of Sikhism, regarded by Sikhs as their final sovereign Guru after Guru Gobind Singh.
Khalsa: In Sikhism, Khalsa refers to both a special group of initiated Sikh warriors and also to all baptized Sikhs more generally. It's like an exclusive club within Sikhism with specific rules and rituals.
Langar: This is a community kitchen run in every gurdwara (Sikh temple) where free meals are served to all visitors regardless of religion or background - it's like an open-door policy at your home where everyone is welcome for dinner.