Real Dictionary

Iron Age
proper noun: The Iron Age was a period of time which began when people started making things from iron about three thousand years ago.

Iron Age in American English
a phase of many human cultures, often following a Bronze Age, characterized by the introduction and development of iron tools and weapons; specif., in Europe beginning c. 1000 b.c.
noun: the period in the history of humankind, following the Stone Age and the Bronze Age, marked by the use of implements and weapons made of iron

iron age in British English
noun: the last and worst age in the history of the world
noun: the period following the Bronze Age characterized by the extremely rapid spread of iron tools and weapons, which began in the Middle East about 1100 bc