Stone Age

Wiktionary

1. n. archaeology A broad prehistoric period during which humans widely used stone for toolmaking.
2. n. figuratively, informal Any extremely primitive or undeveloped era.
3. n. figuratively The time a particular field was introduced and was in its earliest stages of development.

GNU Webster's 1913

1. n. a supposed prehistoric age of the world when stone and bone were habitually used as the materials for weapons and tools; -- called also flint age. The bronze age succeeded to this.

WordNet 3.0

1. n. (archeology) the earliest known period of human culture, characterized by the use of stone implements