Definition

Noun: 1. A major division of geological time: A "geological era" is a large, fundamental unit of time in Earth's history, used to categorize and study the planet's long-term development. It represents a significant span of time characterized by distinct major events in the geological and biological record. 2. A subdivision of an eon: In the hierarchical structure of geologic time, an era is a subdivision of an eon. Eras are themselves composed of smaller units called periods.

Examples of Usage

• Noun:
  • The Mesozoic Era is often called the "Age of Reptiles."
  • Scientists study rock formations to understand the climate of a past geological era.
  • The transition from the Paleozoic Era to the Mesozoic Era was marked by a mass extinction event.

Advanced Usage

• "to define/characterize a geological era": To describe the major features that distinguish one large span of Earth's history from another.
  • The proliferation of complex life defines the Phanerozoic Eon and its subsequent geological eras.
• Capitalization Convention: The names of specific geological eras (e.g., Cenozoic, Paleozoic) are proper nouns and are capitalized.

Variants and Related Words

• Era (n): While "era" can be used more generally for any long and distinct period of history, "geological era" specifies its use in the science of geology.
• Period (n): A subdivision of a geological era (e.g., the Jurassic Period is within the Mesozoic Era).
• Epoch (n): A subdivision of a geological period.
• Eon (n): The largest division of geologic time, encompassing multiple geological eras.

Synonyms

• Geologic era (n): An alternative, equivalent term.
• Major division of geologic time (n): A descriptive synonym.

Related Phrases

• "to date from a geological era": To have originated during a specific major division of Earth's history.
  • These fossils date from the Precambrian geological era.
• "the dawn/end of a geological era": Refers to the beginning or conclusion of a major time division.
  • The end of the Cretaceous Period marked the close of the Mesozoic geological era.

Noun

1. a major division of geological time; an era is usually divided into two or more periods