A functional group.
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 number of things or persons being in some relation to one another.
A subset of a culture or of a society.
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 baseball club, team, or lineup (composed of nine players).
A playing card with nine pips.
The digit or figure 9.
A nine-millimeter semi-automatic pistol.
A statistical unit of proportion (of reliability, purity, etc.).
Describing a group or set with nine elements.
A numerical value equal to 9; the number following eight and preceding ten.