The first part of the word "economics" is derived from the ancient Greek word "oikos," which referred, more or less, to the household or family estate, at least in the literal sense. In a broader sense the word referred to what was private and personal, rather than what was public and shared. The oikos was a place for private work and the running of personal affairs; citizens -- that is, Greek-born males -- could leave the oikos to enter the "polis" -- that is, the city -- to engage in political decision-making.
The second half of the word "economics" is derived from the ancient Greek word "nomos." In its literal sense "nomos" referred to rules, laws or natural laws/conventions. The word "nomos" could refer to almost any kind of law, whether it was made to suit the household -- for instance, a rule made by the husband -- or whether the law came from the civil government. The word could even refer to "rules of thumb," which were rough guidelines about how something should be done.
The ancient Greeks were not very concerned with what we now call economics. For them, economic matters were necessary, dull and not very important. Economics was something tended to domestically, out of necessity. On the other hand, politics was something that citizens engaged in publicly; here, outside of the oikos, men -- just men, at the time -- made political decisions and sought greatness and distinction. For the ancient Greeks there was no greatness nor distinction to be had through economics.
Today, in the modern West, economics is a major concern for most people, from ordinary citizens paying bills to politicians making budgets and creating fiscal and monetary policy. Today, economics and politics are fused together -- political decisions are often about economics, and economic decisions often have a political aspect to them. Thus, the "oikos" and "nomos" meet -- economics today is about rules, regulations and conventions that affect economic life both domestically and nationally.