The term 'prehistoric tool' refers to tools used by humans before the invention of writing. Two examples of such tools are the CELT and the eolith. A CELT is a stone tool, usually made of flint or other hard stone, that was used for cutting and scraping. An eolith is a primitive stone tool, usually made of quartz or other hard stone, that was used for pounding and grinding. Both of these tools were used by prehistoric humans to make their lives easier.