a device for showing the operating condition of some system
a signal for attracting attention
(chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction
call to remembrance; keep alive the memory of someone or something, as in a ceremony; "We remembered the 50th anniversary of the liberation of Auschwitz"; "Remember the dead of the First World War"
be or provide a memorial to a person or an event; "This sculpture commemorates the victims of the concentration camps"; "We memorialized the Dead"
mark by some ceremony or observation; "We marked the anniversary of his death"
the act of referring or consulting; "reference to an encyclopedia produced the answer"
the most direct or specific meaning of a word or expression; the class of objects that an expression refers to; "the extension of `satellite of Mars' is the set containing only Demos and Phobos"
the relation between a word or phrase and the object or idea it refers to; "he argued that reference is a consequence of conditioned reflexes"
a publication (or a passage from a publication) that is referred to; "he carried an armful of references back to his desk"; "he spent hours looking for the source of that quotation"