annulus
UK[ˈanjʊləs]US[ˈænjələs]
n
A ring-shaped object, structure, or region.
Morpheme Breakdown
annul
us
annul
ring
us
noun suffix
Etymology
The word 'annulus' is a direct borrowing from Latin, where it meant 'a little ring'. It is a diminutive form of the Latin noun 'anus', which simply meant 'ring' or 'circle'. This Latin root can be traced back to the Proto-Indo-European root h₁eh₂no-, meaning 'ring' or 'to bend'. The journey from a simple concept of a circular band to the specific geometric and anatomical term 'annulus' demonstrates how a basic concrete shape provides the foundational logic for more specialized technical terminology in fields like mathematics, biology, and engineering.
Analysis
Structure: annul (ring) + us (noun suffix)
annul (from Latin 'annulus', a diminutive of 'anus', meaning 'ring'); us (a Latin noun suffix used to form nouns, often indicating a state or thing).
Examples
The astronomer observed a dark annulus around the planet.
In botany, the annulus is a ring-like part of a fern sporangium.
The engineer calculated the area of the metal annulus.