A definition of the word 'section' is "any of the more or less distinct parts into which something is or may be divided or from which it is made up."

This is the definition I'd like for us to deal with in order to determine what exactly a section is.

I'm curious about the meaning. Can a section be a disjoint union of two or more sections, or is a section necessarily one connected piece?

I'd like to know if the following sentence constitutes a correct restatement of the definition.

A section is a part of some thing which is a composition of distinct parts or roughly a composition of distinct parts.

I suppose to answer the main question we need to ask ourselves if a 'part' is necessarily one connected piece, provided the manner in which it's being used in the definition.

  • 1
    Have you tried looking at other definitions or usage examples? Most words have multiple distinct but related meanings, not a single definition.
    – Stuart F
    Commented May 15 at 7:35
  • 1
    Section of what? Do you mean a portion of a written text? A region of a city or country? A subset of a geometric object in math? A fragment of fruit? An element of a musical composition? One of possibly several groups of students taking a course meeting at a given time and place and taught by a given instructor? And then there are surgical incisions, and many other distinct senses of the noun section. Context matters. Commented May 15 at 12:38
  • @PaulTanenbaum it looks like a subset in math would fail to meet this particular definition of a section, since there seems to be agreement that a section is never a disjoint union, which a subset is allowed to be. To your point, aren't definitions constructed very carefully in such a way that no possible situation would lead that particular definition to fail?
    – Simon M
    Commented May 16 at 6:03
  • @StuartF do I need to know that there is a color-related definition of the word 'orange' in order to understand the fruit-related definition of the word 'orange'? I always got the impression that you can always deal with one particular definition on its own terms and completely ignore the others, unless your goal is a very broad understanding of how the word is used in all contexts, which isn't my goal here at all. Sure, since distinct definitions are often related, reading the other definitions can improve your intuition of any one particular definition, but it's not strictly necessary.
    – Simon M
    Commented May 16 at 6:08

2 Answers 2


No, sections are not normally disjoint unions of sections.

However, if there's a hierarchical organization of the whole collection, it may be divided into sections at multiple levels. Sometimes we give different names to the sections at each level, such as "chapter", "paragraph", and "clause". In other cases we just use "section", "sub-section", "sub-sub-section", and so on. And it's also possible to mix both styles.

The important thing about this organization is that the larger sections combine closely related smaller sections. You can view this like a pizza or cake that's cut into slices. You can start with large slices, then divide each of them into smaller slices. But you can't take two unrelated slices and call that a slice.

A better term for a subset of a whole that shares some common trait would be "portion". For example, if you make a pizza where a disconnected set of slices have pepperoni, you could refer to them as the pepperoni portion of the pizza.

But even that might suggest connection, because it's singular, so I think it would be more likely to just say "the pepperoni slices".

  • That is illuminating. That means if my pizza alternates slices between pepperoni and cheese-only slices, then the totality of the cheese-only slices is NOT a section of the pizza, unless we rearrange the slices so that pepperoni is on one side of a divide straight down the middle of the pizza, and cheese-only makes up the other half.
    – Simon M
    Commented May 16 at 5:55
  • Then again, if a pizza does indeed alternate between two styles every other slice and one of the styles is cheese-only, I wouldn't blame anyone for claiming there is a cheese-only section of the pizza in the interest of brevity. While technically incorrect, "the cheese-only section" is far more efficient than "the totality of slices which are cheese-only", so I'd look past it. I wonder if there is an equally efficient method of referring to the cheese-only slices that does not rely on a misuse of a word. "Cheese-only union" might work but would not make sense to most audiences.
    – Simon M
    Commented May 16 at 9:24
  • @SimonM I would say "cheese-only portion" rather than section if the slices are not connected to each other.
    – Barmar
    Commented May 16 at 14:51

"Section" derives from the Latin secare, which means "to cut." Therefore, "section" (having come into English from French) originally meant "that which has been cut from something."

Another example of this etymology is "sect." A religious sect is a distinct group within a religion but is cut from the same cloth.

Can a section be a disjoint union of two or more sections, or is a section necessarily one connected piece?

This depends on context. One section of something is composed of other sections. A tail is both a distinct section of a cat and a collection of sections (bones, skin, fur, etc.).

My answer to your question is "no, not without jumping horses mid-river context-wise."

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