chron
1. A small unit of geologic time, equivalent to the chronostratigraphic unit chronozone, usually based on fossil zonation (see BIOCHRON). When used formally (e.g. Gilbert Chron) the initial letter is capitalized.

2. A single time interval of constant polarity of the geomagnetic field (polarity chron).

chron A subdivision of geological time based on the direction of magnetization, as preserved in rocks of the period. Within many chrons there are shorter periods of alternate magnetization (subchrons). The two most recent chrons in Earth history are the Matuyama (reversed) and Brunhes (normal).

chron
1. A small unit of geologic time, equivalent to the chronostratigraphic unit chronozone, that is usually based on fossil zonation. When used formally (e.g. Gilbert Chron) the initial letter is capitalized.

2. (polarity chron) A single time interval of constant polarity of the geomagnetic field.