The term 'PART OF THE UNDERGROUND ECONOMY' can be summarized by the three-letter word ORE. The UNDERGROUND ECONOMY is a term used to describe economic activities that are not reported or recorded in official government statistics. It includes activities such as bartering, cash-in-hand work, and tax evasion. ORE is an acronym for Off-the-Record ECONOMY, which is a subset of the UNDERGROUND ECONOMY. It refers to activities that are not reported to the government, but are still conducted within the legal framework.