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1. A period marked by distinctive character or reckoned from a fixed point or event
   - era
    
2. (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded
   - date of reference
    
3. A unit of geological time that is a subdivision of a period and is itself divided into ages
    
4. (machine learning) one iteration of learning with a sample of training data

Derived forms: epochs

Type of: date, geologic time, geological time, period, period of time, time period, time span

Part of: geological period, period

Encyclopedia: Epoch, George