1. An alternative name for the Middle Jurassic epoch, which is dated at 175.6–161.2 Ma ago (Int. Commission on Stratigraphy, 2004). It is preceded by the Early Jurassic, followed by the Late Jurassic, and comprises the Aalenian, Bajocian, Bathonian, and Callovian stages. Some authors do not recognize the Aalenian as a separate age, including it instead within an enlarged Bajocian age.
2. The name of the corresponding European series, which is roughly contemporaneous with the uppermost Herangi and lower Kawhia (New Zealand).
3. A lithostratigraphic unit in the Aalenian of Yorkshire, England.