Carboniferous

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Of, belonging to, or denoting a geologic division of the Paleozoic Era following the Devonian and preceding the Permian, including the Mississippian Period and the Pennsylvanian Period and characterized, especially in the Pennsylvanian, by swamp formation and deposition of plant remains later hardened into coal.
2. adj. Producing or containing carbon or coal.
3. n. The Carboniferous Period. See Table at geologic time.

Century Dictionary and Cyclopedia

1. Containing or yielding carbon or coal. In geology, almost exclusively used in designating that assemblage of strata from which the coal of England, France, Germany, and the United States is for the most part obtained. The Carboniferous series is of the Paleozoic age, and is the most recent portion of the Paleozoic. It is overlaid by the Permian rocks, which belong to the closing era of the Carboniferous age, and is underlaid by the Devonian. The Carboniferous, over large areas both in Europe and North America, is separable into three more or less distinct groups: the coal-measures, the millstone-grit, and the mountain limestone. The first of these three is a series of shales and clays, with which the coal-beds themselves are inter-stratified. This part of the series is sometimes several thousand feet in thickness, and the number and thickness of the intercalated coal-beds differ greatly in different regions. The millstone-grit is a detrital rock ordinarily quite silicious, and assuming all degrees of fineness, from that of a fine-grained gritstone to that of a coarse conglomerate. Its thickness varies greatly in various regions. The mountain limestone is a calcareous rock, often rich in fossils of marine origin, and sometimes having a thickness of over 3,000 feet. See coal, coal-measures, millstone-grit, and mountain limestone (under limestone).

Wiktionary

1. adj. of a geologic period within the Paleozoic era; comprises the lower, middle and upper Mississippian and lower, middle and upper Pennsylvanian epochs from about 345 to 280 million years ago, when coal was laid down
2. n. the Carboniferous period

GNU Webster's 1913

1. adj. Producing or containing carbon or coal.

WordNet 3.0

1. adj. of or relating to the Carboniferous geologic era
2. adj. relating to or consisting of or yielding carbon
3. n. from 345 million to 280 million years ago