Black tuxedo jacket and matching trousers. Formal (piquÃ© or pleated front) white shirt. Shirt studs and cuff links. Black bow tie (silk, satin, or twill) Black cummerbund to match tie, or a vest. Dressy braces to ensure a good fit (optional) No gloves. Black patent shoes and black dress socks.
GCIDE(0.00 / 0 votes)Rate this definition: 1  Datum(n.) a single piece of information; a fact; especially a piece of information obtained by observation or experiment; -- used mostly in the plural. 2  Datum(n.) (Surveying) a point, line, or level surface used as a reference in measuring elevations. RHUD.
Quick Answer. A datum line is a point of reference or standard for comparison. The term is primarily used in reference to surveying and engineering, where it is used in the measurement of depths and heights. Continue Reading.