Category vs Null - What's the difference?

category | null |

As nouns the difference between category and null

is that category is a group, often named or numbered, to which items are assigned based on similarity or defined criteria while null is zero, nil; the cardinal number before einn.

category

English

(wikipedia category)

Noun

(categories)
• A group, often named or numbered, to which items are assigned based on similarity or defined criteria.
• *
• The traditional way of describing the similarities and differences between constituents is to say that they belong to categories'' of various types. Thus, words like ''boy'', ''girl'', ''man'', ''woman'', etc. are traditionally said to belong to the category''' of Nouns, whereas words like ''a'', ''the'', ''this'', and ''that'' are traditionally said to belong to the ' category of Determiners.
This steep and dangerous climb belongs to the most difficult category .
I wouldn't put this book in the same category as the author's first novel.
• (mathematics) A collection of objects, together with a transitively closed collection of composable arrows between them, such that every object has an identity arrow, and such that arrow composition is associative.
• One well-known category has sets as objects and functions as arrows.
Just as a monoid consists of an underlying set with a binary operation "on top of it" which is closed, associative and with an identity, a category consists of an underlying digraph with an arrow composition operation "on top of it" which is transitively closed, associative, and with an identity at each object. In fact, a category's composition operation, when restricted to a single one of its objects, turns that object's set of arrows (which would all be loops) into a monoid.

Synonyms

* (group to which items are assigned) class, family, genus, group, kingdom, order, phylum, race, tribe, type * See also

Derived terms

* category mistake * category theory * conceptual category * perceptual category * subcategory * supercategory

null

English

Noun

(en noun)
• A non-existent or empty value or set of values.
• Zero]] quantity of [[expression, expressions; nothing.
• (Francis Bacon)
• Something that has no force or meaning.
• (computing) the ASCII or Unicode character (), represented by a zero value, that indicates no character and is sometimes used as a string terminator.
• (computing) the attribute of an entity that has no valid value.
• Since no date of birth was entered for the patient, his age is null .
• One of the beads in nulled work.
• (statistics) null hypothesis

• Having no validity, "null and void"
• insignificant
• * 1924 , Marcel Proust, Within a Budding Grove :
• In proportion as we descend the social scale our snobbishness fastens on to mere nothings which are perhaps no more null than the distinctions observed by the aristocracy, but, being more obscure, more peculiar to the individual, take us more by surprise.
• absent or non-existent
• (mathematics) of the null set
• (mathematics) of or comprising a value of precisely zero
• (genetics, of a mutation) causing a complete loss of gene function, amorphic.

* nullity

Verb

(en verb)
• to nullify; to annul
• (Milton)