The term 'historic time piece' can be summarized as a clock or watch that has been around for a long period of time. The crossword solution for this term is 'ERA', which is a three letter word that refers to a period of time in history. This could refer to a specific ERA, such as the Victorian ERA, or it could refer to a longer period of time, such as the Middle Ages. Historic time pieces are often highly valued and sought after due to their age and craftsmanship.