This word might look almost identical to the word “more,” the comparative pronoun meaning “a greater or additional amount of something,” but the added “s” changes the definition and pronunciation (MOR-ayz). The plural noun “mores” comes from the plural of the Latin word for “custom,” so it’s easy to remember as the accepted customs of a society. For example, tipping service workers is part of the common mores in the United States, but in most European countries, gratuity is already included in the bill, and no tip is required. The word was invented in the late 19th century by William Graham Sumner, one of the first sociologists from the United States, and “mores” continues to be an important term in the field of sociology.