The term era (not aera , as incorrectly written) is Spanish, signifying time, as in the phrase, de era en era, "from time to time." It was first used in the Era Hispanica, instituted B.C. 38, in honour of Augustus, when Spain was allotted to him in the distribution of the provinces among the second triumvirate, Augustus, Anthony, and Lepidus. It now usually denotes an indefinite series of years, beginning from some known epoch; and so differs from a period which is a definite series: as the era of the foundation of Rome, the era of the Olympiads, the era of Nabonassar, &c. See EPOCH .