|1.||[ adjective ] (geology) coming next after the third and just before the fifth in position or time or degree or magnitude|
"the quaternary period of geologic time extends from the end of the tertiary period to the present"
|2.||[ adverb ] in the fourth place|
"fourthly, you must pay the rent on the first of the month"
|3.||[ noun ] following the third position; number four in a countable series|
|4.||[ noun ] (mathematics) one of four equal parts|
|Synonyms:||quarter one-fourth twenty-five_percent quartern fourth_part|
"a quarter of a pound"
|Related terms:||common_fraction quarter|
|5.||[ noun ] (music) the musical interval between one note and another four notes away from it|