In terms of socio-economic impact, it appears that the water mill was an oppidan development in the Roman possessions, including Dacia.

I wol nat tellen / of hir strange sewes / Ne of hir swannes / nor of hire heronsewes […].

examples of clusters would include in accordance with, the results of and so far

Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too. GDP measures the total value of output in an economic territory. Its apparent simplicity explains why it is scrutinised down to tenths of a percentage point every month.