A number of things or persons being in some relation to one another.
A column in the periodic table of chemical elements.
An element of an espresso machine from which hot water pours into the portafilter.
A (usually small) group of people who perform music together.
An air force formation.
A number of users with the same rights with respect to accession, modification, and execution of files, computers and peripherals.
A subset of a culture or of a society.
A functional group.
A small number (up to about fifty) of galaxies that are near each other.
A collection of formations or rock strata.
A number of eighth, sixteenth, etc., notes joined at the stems; sometimes rather indefinitely applied to any ornament made up of a few short notes.
A set with an associative binary operation, under which there exists an identity element, and such that each element has an inverse.
A commercial organization.
A set of teams playing each other in the same division, while not during the same period playing any teams that belong to other sets in the division.
To come together to form a group.
To put together to form a group.
A single object, especially one of a group.
A single consonant, as opposed to a geminated consonant.
A playing card that is the only one of its suit in a hand, especially at bridge.
A person without a romantic partner.
A hand containing only one card of a certain suit.
A set with exactly one element.
A child or animal that is born singly, not as a twin or other multiple birth.
A person without a dissociative identity.
A class that may not be instantiated more than once, i.e. that implements the singleton design pattern.