datum

Concise Oxford English Dictionary © 2008 Oxford University Press:
datum /ˈdeɪtəm/

▶noun (pl. data) See also data.

• 1 a piece of information.

• 2 an assumption or premise from which inferences may be drawn.

• 3 a fixed starting point of a scale or operation.

– origin C18: from L., lit. ‘something given’.