# acanthin

CEFR C2 · Noun

Source: https://englishreference.com/word/acanthin
Updated: 2026-06-22

## Definition

a hard, spiny part of a sea urchin's body. It is a tiny, sharp structure that helps protect the animal from predators.

For teachers: a calcified, spiny platelet found in the test of a sea urchin. It forms part of the skeletal structure and contributes to the animal's defensive armor.

## Examples

- The sea urchin's acanthin helps protect it.
- Marine biologists examined the acanthin of the specimen to determine its specific species and age.
- The intricate arrangement of acanthin and other skeletal elements provides the sea urchin with a robust exoskeleton capable of withstanding significant mechanical pressure from the ocean floor.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.