- Calymmian (Wikipedia)
The Calymmian Period (from Ancient Greek: κάλυμμα, romanized: kálymma, meaning “cover”) is the first geologic period in the Mesoproterozoic Era and lasted from 1600 Mya to 1400 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
- Lord–bondsman dialectic (Wikipedia)
The lord–bondsman dialectic (sometimes translated master–slave dialectic) is a famous passage in Georg Wilhelm Friedrich Hegel’s Phenomenology of Spirit. It is widely considered a key element in Hegel’s philosophical system, and it has heavily influenced many subsequent philosophers.