(astronomy) Any astronomical object of known absolute magnitude. Its distance can then be calculated from its apparent magnitude.

Time as measured by synchronizing clocks in different geographical locations within a time zone to the same time, rather than using the local meridian, as in local mean time or solar time.

plural of standard candle

An agreed method of measuring time; a specification or standard of either the rate at which time passes, or of points in time, or of both.

(rail transport) A track gauge of 56.5 inches (1435 mm).

(linguistics) The form of the English language widely accepted as the usual correct form.

(astronomy) Any astronomical object of known diameter whose distance can then be calculated from the angle it subtends

plural of standard ruler

A lamp supported by a tall vertical pole in order that light comes from above those seated in the vicinity.

(sociolinguistics) A form of a language that is institutionally promoted, regarded as the most "correct" or neutral variety; used by a population for public and formal purposes.