sand dollar

Thân thiện

A child holds a sand dollar found on the beach.

Definition

1. Noun:
   • A type of marine animal that is a flat, round, and rigid echinoderm, closely related to sea urchins. Its skeleton (called a test) is often found washed up on beaches and resembles a large, bleached coin.

Usage

• The term "sand dollar" is used to refer to the living animal in its marine habitat or, more commonly, to its distinctive white skeleton found on beaches.
• It is a countable noun (e.g., one sand dollar, many sand dollars).

Examples

• Noun:
  • We found a perfect, whole sand dollar on the beach.
  • Living sand dollars burrow just beneath the surface of sandy ocean floors.

Advanced Usage

• "Test of a sand dollar": Refers specifically to the hard, internal skeleton or shell of the animal, which is what is typically collected.
  • The test of a sand dollar is covered in a pattern that looks like a flower.

Variants and Related Words

• Clypeasteroid (n): The scientific order name for sand dollars.
• Sea biscuit (n): A common name for a related, often thicker, type of sand dollar.
• Test (n): The biological term for the hard skeleton of echinoderms like sand dollars and sea urchins.

Synonyms

• Echinoid: A broader term for sea urchins and related animals, including sand dollars.

Học thuật

Noun

1. flattened disklike sea urchins that live on sandy bottoms