epoch
noun
- moment in time used as a reference point for some time-varying astronomical quantity
- reference point from which time is measured
- date and time from which a computer measures system time
Wiktionary
Pronunciation: /ˈiːpɒk/ / /ˈɛpɒk/ / /ˈɛpək/
noun
Etymology: From Medieval Latin epocha, from Ancient Greek ἐποχή (epokhḗ, “a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch”), from ἐπέχω (epékhō, “to hold in, check”), from ἐπι- (epi-, “upon”) + ἔχω (ékhō, “to have, hold”). Doublet of epoche.
- A particular period of history, or of a person's life, especially one considered noteworthy or remarkable.
“I grew bitter in my words—I believed the worst of everyone; nay, I sometimes doubted the affection of my kind, my indulgent parents. But let me hastily pass over this vain and profitless epoch,—the fierce tempest, and the weary calm, were but the appointed means by which I reached the harbour of faith and rest.”
“And it occasionally happens that a period in which one had, hitherto, been mainly looking for the coming to birth of new things, suddenly reveals itself as an epoch of fading and decay.”
- A notable event which marks the beginning of such a period.
- A specific instant in time, chosen as the point of reference or zero value of a system that involves identifying instants of time.
“UNIX epoch; J2000 epoch”
“Appendix A gives formulae for the calculation of the orbital elements of the planets at any time referred to the mean ecliptic and equinox of the epoch of noon on 1st January 2000; this is called the J2000 epoch.”
- A geochronologic unit of hundreds of thousands to millions of years; a subdivision of a period, and subdivided into ages (or sometimes subepochs).
“Now during the time of the glacial epoch the greatest distance of the sun in winter was 98¼ millions of miles, whereas it is now, in winter, only 91½ millions of miles, the mean distance being taken as 93 million miles.”
“Phoenix and Lubbock are both caught in severe drought, and it is going to get much worse. We may see many such [dust] storms in the decades ahead, along with species extinctions, radical disturbance of ecosystems, and intensified social conflict over land and water. Welcome to the Anthropocene, the epoch when humans have become a major geological and climatic force.”
- One complete presentation of the training data set to an iterative machine learning algorithm.
“The neural network was trained over 500 epochs.”
“For now, let's test and evaluate our GAN by comparing the results from the first epoch with the generated images from the last epoch.”
verb
Etymology: From Medieval Latin epocha, from Ancient Greek ἐποχή (epokhḗ, “a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch”), from ἐπέχω (epékhō, “to hold in, check”), from ἐπι- (epi-, “upon”) + ἔχω (ékhō, “to have, hold”). Doublet of epoche.
- To divide (data) into segments by time period.
“The continuous data were epoched into segments of 1500 ms (starting 500 ms before visual stimulus onset), time-locked to stimulus onset (0 ms) and sorted according to experimental conditions.”