Definition

Noun: A rotifer is a very small, mostly aquatic animal that is multicellular. It is characterized by having a distinctive, ciliated (hair-like) structure at its front end that looks and functions like a rotating wheel. This structure is used for both feeding and movement. Rotifers are a common component of freshwater plankton.

Examples

• Under the microscope, the rotifer's whirling cilia create currents to draw in food particles.
• Scientists study the population density of rotifers as an indicator of water quality in the lake.
• A single drop of pond water may contain dozens of these tiny rotifers.

Advanced Usage

• In scientific classification: The term "rotifer" refers to any member of the phylum Rotifera. They are studied in fields like limnology (the study of inland waters) and ecology.
  • The biodiversity survey noted a high abundance of bdelloid rotifers in the sediment samples.

Variants and Related Words

• Rotifera (proper noun): The scientific phylum name to which all rotifers belong.
• Planktonic (adjective): Describing organisms, like many rotifers, that drift in water currents.
  • The planktonic rotifers are a crucial food source for small fish.

Synonyms

• Wheel animalcule: An older, descriptive synonym based on the rotifer's appearance under a microscope.

Notes on Meaning

The definition of rotifer is highly specific to zoology and microbiology. It does not have different common meanings. Its usage is almost exclusively scientific or educational, referring to this particular type of microscopic invertebrate.

Noun

1. minute aquatic multicellular organisms having a ciliated wheel-like organ for feeding and locomotion; constituents of freshwater plankton