coccus

C2
UK/ˈkɒkəs/US/ˈkɑːkəs/

Technical/Scientific

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Definition

Meaning

Any spherical or roughly spherical bacterium.

The term can also refer to certain types of spherical or rounded cells found in plants (e.g., berries of certain plants) or other organisms, but the primary biological use pertains to spherical bacteria.

Linguistics

Semantic Notes

A singular bacterium is a coccus; the plural is cocci. It's a basic morphological classification of bacteria, contrasting with 'bacillus' (rod-shaped) and 'spirillum' (spiral-shaped).

Dialectal Variation

British vs American Usage

Differences

Spelling and pronunciation are consistent between UK and US English for this scientific term.

Connotations

None; it is a neutral, technical term in both regions.

Frequency

Used with identical frequency and meaning in biological/medical contexts in both UK and US English.

Vocabulary

Collocations

strong
staphylostreptogram-positivebacterialspherical
medium
diploarrangementmicroscopicpathogeniccluster
weak
identifiedobservedculturesampleform

Grammar

Valency Patterns

[adjective] + coccuscoccus + of + [genus/species]

Vocabulary

Synonyms

Strong

micrococcus (when referring to genus Micrococcus)staphylococcus (when referring to genus Staphylococcus)

Neutral

spherical bacterium

Weak

round cellsphere-shaped cell

Vocabulary

Antonyms

bacillusrodspirillum

Phrases

Idioms & Phrases

  • No idioms exist for this technical term.

Usage

Context Usage

Business

Not used.

Academic

Primary usage; common in microbiology, medicine, and biological science textbooks and research papers.

Everyday

Rarely used outside scientific contexts.

Technical

Core term; essential for describing bacterial morphology.

Examples

By Part of Speech

verb

British English

  • No verb form exists.

American English

  • No verb form exists.

adverb

British English

  • No adverb form exists.

American English

  • No adverb form exists.

adjective

British English

  • No standard adjective form. 'Coccal' is used technically (e.g., coccal infection).

American English

  • No standard adjective form. 'Coccal' is used technically (e.g., coccal infection).

Examples

By CEFR Level

A2
  • Not applicable for this C2-level word.
B1
  • Under the microscope, some bacteria look like little balls; these are called cocci.
B2
  • The lab report identified the pathogen as a gram-positive coccus, requiring specific antibiotics.
C1
  • Streptococcus pneumoniae, a lancet-shaped diplococcus, is a major cause of community-acquired pneumonia.

Learning

Memory Aids

Mnemonic

Think of 'coccus' sounding like 'cocoa' beans, which are roughly spherical, to remember it describes a round-shaped bacterium.

Conceptual Metaphor

Often conceptualized as a 'BALL' or 'BEAD' (e.g., 'a chain of beads' for streptococci).

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

  • Avoid direct translation from Russian 'кокк' without understanding the precise microbiological context. It is not a generic word for 'germ' or 'bacteria'.

Common Mistakes

  • Pronouncing it like 'cock-us' with a hard /k/ sound; the first 'c' is hard /k/, the second is soft /s/.
  • Using it as a general term for any bacteria; it is a specific shape classification.

Practice

Quiz

Fill in the gap
Bacteria are often classified by shape; a spherical one is called a .
Multiple Choice

What is the plural form of 'coccus'?

FAQ

Frequently Asked Questions

No. 'Coccus' describes the spherical shape. 'Staphylococcus' is a specific genus of bacteria that are cocci arranged in clusters.

It is highly unlikely. It is a specialized term used almost exclusively in scientific or medical contexts.

In bacteriology, the primary antonym is 'bacillus,' referring to a rod-shaped bacterium.

In British English: /ˈkɒkəs/ (KOK-uhs). In American English: /ˈkɑːkəs/ (KAH-kuhs).