The term 'Britannica' is a reference to the Encyclopaedia Britannica, which is an encyclopedia published by Encyclopaedia Britannica, Inc. It is one of the oldest and most comprehensive encyclopedias in the world, having been first published in 1768. The crossword solution for this term is 'pax', which is a Latin word meaning 'PEACE'. Pax is often used as a greeting or salutation, and is also used to refer to a period of PEACE or tranquility.