group

Less common meanings

6. 6
   table columnnouncountable

   A vertical column in the periodic table, containing elements that share similar chemical behavior.

   Chlorine sits in the same group as fluorine and bromine.

   The elements of group 18 are the noble gases.

   Similarfamily

   Note

   Chemistry has two groups, and this is the one on the chart. Elements in the same column have similar outer electron arrangements, which is why their behavior recurs; the modern IUPAC system numbers the columns 1 through 18, so group 18 means the noble gases. The other, the cluster of atoms, lives inside a molecule, not on the table. Source

   Checked 30 Oct 2026 · 4 facts

   • This is not universal: helium has two valence electrons, whereas neon has eight, although both belong to group 18. openstax.org
   • Recurring chemical behavior reflects similarities in outer electron shells. openstax.org
   • IUPAC numbers the periodic-table groups from 1 through 18. iupac.org
   • Group 18 contains the noble gases. openstax.org
7. 7
   atom clusternouncountable

   A cluster of atoms within a molecule responsible for that molecule's characteristic chemical reactions.

   The carboxyl group gives organic acids their sour, reactive character.

   Chemists modify a single group to change how a compound behaves.

   Note

   Organic chemists shorten functional group to plain group once the context is clear. Hydroxyl, carbonyl, amino and nitro are groups in this sense, and they are described by what they do to the molecule around them: nitro is an electron-withdrawing group. Its characteristic reactions stay largely the same whatever carbon skeleton carries it. Source

   Checked 30 Oct 2026 · 6 facts

   • Hydroxyl is an atomic group within molecules. chem.ucla.edu
   • Carbonyl is an atomic group within molecules. chem.ucla.edu
   • Amino is an atomic group within molecules. chem.ucla.edu
   • Nitro is an atomic group within molecules. chem.ucla.edu
   • Nitro is electron-withdrawing. openstax.org
   • A functional group's characteristic chemical behavior remains broadly similar in different molecules. openstax.org
8. 8
   algebranouncountable

   In mathematics, a set together with an operation that combines any two elements, is associative, has an identity element, and gives every element an inverse.

   The integers under addition form a group with zero as the identity.

   Mathematicians classify finite groups by their internal structure.

   Note

   The founding object of group theory, and a word mathematicians rarely leave bare: a qualifier in front names a family with a special property or extra structure, as in finitely presented groups, Fuchsian groups or Lie groups. A part of a group that is itself a group is a subgroup. The term reaches beyond pure mathematics too. Zhong-Qi Ma's Group Theory for Physicists (2007) introduces Lie groups to physicists. Source

   Checked 30 Oct 2026 · 4 facts

   • Qualifiers can specify properties or extra structure. Finite presentability is a property: the group admits a presentation with finitely many generators and relations. gap-system.github.io
   • A subset that forms a group under the inherited operation is a subgroup. web.williams.edu
   • Zhong-Qi Ma wrote Group Theory for Physicists. books.google.rw
   • The book covers Lie groups for a physics readership, demonstrating application beyond pure mathematics. books.google.com
9. 9
   user permissionsnouncountable

   A set of computer users who share the same rights to open, change, and run files and devices.

   The administrator placed the new account in the developers group.

   Several groups were created to separate staff accounts from guests.

   Note

   A computing group exists to hand out permissions in bulk. Instead of granting rights account by account, an administrator grants them to the group, and every member can then access, modify or execute the same files, machines and peripherals. Adding someone to a group or removing them is how their rights change. Source

   Checked 30 Oct 2026 · 4 facts

   • Groups allow administrators to assign permissions collectively instead of separately to individual accounts. learn.microsoft.com
   • Group members share the group's permissions to read, modify or execute files. docs.redhat.com
   • Group permissions can govern access to hardware devices and peripherals. wiki.ubuntu.com
   • Adding or removing group members is a way to manage their access rights. learn.microsoft.com
10. 10
    air unitnouncountable

    A military aviation formation, typically composed of two or more squadrons.

    The bomber group lost three aircraft over the Channel.

    She was promoted to command an air group of four transport squadrons.

    Note

    Air forces use the word for a rung in their chain of command. In the US Air Force a group brings two or more squadrons under one commander, below the wing, while in the RAF a group is a much larger formation above the wing. It is commonly named for its role, as a bomber or reconnaissance group. Source

    Checked 30 Oct 2026 · 5 facts

    • A group is an echelon in an air force's chain of command. afhra.af.mil
    • A US Air Force group brings together two or more squadrons under a group commander, below wing level. en.wikipedia.org
    • An RAF group is a larger formation above wing level. raf.mod.uk
    • Groups commonly have designations describing their role. static.e-publishing.af.mil
    • Bombing and reconnaissance are examples of roles reflected in group designations. media.defense.gov
11. 11
    joined notesnouncountable

    Several eighth, sixteenth, or shorter notes joined at the stems; sometimes applied loosely to any ornament built from a few short notes.

    The pianist rushed through a group of sixteenth notes in the final measure.

    Each group is beamed together to show the rhythm.

    Note

    On the page a group is what the beam makes: eighth, sixteenth and shorter notes joined at their stems so the eye reads the beat in units. The looser use, for any ornament built from a few rapid notes, is less exact, so when the talk is of notation, the beamed sense is the safer reading. It has nothing to do with the band. Source

    Checked 30 Oct 2026 · 3 facts

    • A musical group can consist of eighth, sixteenth, or shorter notes joined at their stems. en.wiktionary.org
    • Beaming helps readers recognize rhythmic units corresponding to beats. open.edu
    • Group also has a less precise musical sense covering ornaments composed of a few short notes. en.wiktionary.org
12. 12
    curve pointsnounarchaic

    An effective divisor on an algebraic curve: a formal sum of points on the curve with non-negative whole-number multiplicities.

    Note

    An older geometer's name for what is now called an effective divisor, such as the points in which a curve is met by another curve or by one line of a pencil. Source

    Checked 2 Nov 2026 · 2 facts

    • Group is a historical geometrical term for an effective divisor on a curve. en.wikipedia.org
    • Intersection points with another curve provide examples of these historical groups. math.univ-lyon1.fr
13. 13
    nouncolloquialuncountable

    Short for group therapy: sessions in which a therapist leads several people in talking through their problems together.

    He's been going to group every week since he quit drinking, and it's helping.

    What gets said in group stays in group.

    UsageNo article in go to group and in group, like go to school.

14. 14
    noun

    A collection of related rock formations or strata treated as a single stratigraphic unit.
15. 15
    noun

    A small collection of up to about fifty galaxies that lie near one another in space.
16. 16
    noun

    The component of an espresso machine from which hot water flows into the portafilter.