A measurement one can compare (some other measurement) to.

Information about a person, provided by someone (a referee) with whom they are well acquainted.

(UK, Ireland) A person who provides this information; a referee.

(often attributive) A reference work.

The act of referring: a submitting for information or decision.

(semantics) A relation between objects in which one object designates, or acts as a means by which to connect to or link to, another object.

(academic writing) A short written identification of a previously published work which is used as a source for a text.

(academic writing) A previously published written work thus indicated; a source.

(computing) An object containing information which refers to data stored elsewhere, as opposed to containing the data itself.

(programming, character entity) A special sequence used to represent complex characters in markup languages, such as ™ for the ™ symbol.

To provide a list of references for (a text).

To refer to, to use as a reference.

To mention, to cite.

(programming) To contain the value that is a memory address of some value stored in memory.