facultative

USAGE SUMMARY

The phrase "facultative" is correct and usable in written English.
It is typically used in scientific or technical contexts to describe something that is optional or not strictly necessary, often referring to biological or ecological processes. Example: "Some species are facultative anaerobes, meaning they can survive with or without oxygen."

✓ Grammatically correct

Science

Encyclopedias

News & Media

Human-verified examples from authoritative sources

Exact Expressions

32 human-written examples

Some species, called facultative anaerobes, are able to grow either with or without free oxygen.

Encyclopedia Britannica

Endosymbionts include commensals, facultative parasites, and obligate parasites; the latter category embraces forms that have effects on their hosts ranging from mild discomfort to death.

Encyclopedia Britannica

Obligate parasites have an absolute requirement for a host, whereas facultative parasites can live and reproduce in the absence of a host.

Encyclopedia Britannica

Its species are microbiologically characterized as gram-negative, nonmotile, facultative anaerobes (not requiring oxygen) that have a fermentative type of metabolism.

Encyclopedia Britannica

51] does not occur in facultative anaerobic organisms or in strict aerobes, however.

Encyclopedia Britannica

Haustoria, which may be short, bulbous protrusions or large branched systems filling the whole cell, are characteristically produced by obligate (i.e., invariably parasitic) parasites; some facultative (i.e., occasionally parasitic) parasites also produce them.

Encyclopedia Britannica

Some bacteria extracted from a meteorite were facultative aerobes.

Encyclopedia Britannica

Equipped with green leaves, the plant is able to photosynthesize and provide its own nutrition, but acts as facultative parasite and steals water from its neighbors as necessary (which enables both its size and dry-season flowering).

Britannica

All Haemophilus are gram-negative, aerobic or facultative anaerobic and nonmotile and require a growth factor that is found in blood.

Encyclopedia Britannica

The coliforms are facultative anaerobic (not requiring oxygen), nonsporulating, rod-shaped bacteria that produce acid and gas from the fermentation of lactose sugar: e.g., Escherichia coli, Enterobacter aerogenes, and Klebsiella pneumoniae.

Encyclopedia Britannica

Vibrios are microbiologically characterized as gram-negative, highly motile, facultative anaerobes (not requiring oxygen), with one to three whiplike flagella at one end.

Encyclopedia Britannica

Expert writing Tips

Best practice

When using "facultative" in scientific writing, clearly define the specific context in which the term applies, especially when describing biological processes or characteristics. This avoids ambiguity and ensures clarity for the reader.

Common error

Avoid confusing "facultative", which means optional or adaptable, with "facilitative", which means helping to bring about an outcome. Using the wrong term can significantly alter the intended meaning of your sentence.

Linguistic Context

The primary grammatical function of "facultative" is as an adjective. It modifies nouns to indicate something is optional or adaptable. Ludwig provides numerous examples, particularly in the context of biology, where it describes organisms or processes that can function under varying conditions.

Expression frequency: Common

Frequent in

Science

35%

Encyclopedias

35%

News & Media

15%

Less common in

Formal & Business

5%

Reference

5%

Wiki

5%

Ludwig's WRAP-UP

In summary, "facultative" is an adjective primarily used in scientific and technical fields to denote something optional or adaptable. Ludwig AI's analysis confirms its correct grammatical standing and highlights its common usage in biology and related sciences. When using "facultative", ensure that the context clearly defines the specific conditions under which the term applies. Be mindful of potential confusion with similar-sounding words like "facilitative". While predominantly found in formal and scientific registers, its adaptability makes it a valuable term for expressing optionality across various domains.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

not obligate

Directly states the lack of a requirement or obligation.

optional

Emphasizes the non-mandatory nature of a process or characteristic.

non-essential

Underscores that something is not absolutely required.

elective

Highlights the element of choice or selection.

adaptive

Focuses on the ability to adjust to different conditions.

flexible

Implies a capacity to bend or change easily, rather than being rigid.

discretionary

Indicates that something is done based on individual judgment.

permissive

Highlights the allowance of alternative options.

capable of adaptation

Highlights the ability to change and adjust to new conditions or environments.

able to adjust

Emphasizes the ability to modify behavior or characteristics based on circumstances.

FAQs

How is "facultative" used in biology?

In biology, "facultative" describes organisms or processes that can function under different conditions, such as a "facultative anaerobe" that can live with or without oxygen.

What's the difference between "facultative" and "obligate"?

"Facultative" means optional or adaptable, while "obligate" means required or necessary. For example, a "facultative parasite" can live without a host, but an obligate parasite cannot.

What are some synonyms for "facultative" in a general context?

In a non-scientific context, you can use synonyms such as "optional", "elective", or "discretionary" instead of "facultative".

Can "facultative" apply to human behavior or traits?

Yes, though less common, "facultative" can describe behaviors or traits that are adaptable or not strictly necessary, but this usage is more frequent in scientific or technical contexts.