n. The science that explains, by the law of causation, the past condition and changes of the Earth.
the GNU version of the Collaborative International Dictionary of English
n. The science which explains, by the law of causation, the past condition and changes of the earth; the explanation of past events in terms of scientific causes, such as geological causes.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the explanation of past events in terms of scientific causes (as geological causes)