The exchange of goods and services through the use of money.

I made an addition or two to the article. Your definition is one that many people would suppose to be the case. But in political discourse, (or traffic, or in "the political marketplace) "markets" mean something more, less, and other than mere "exchange of goods and services through the use of money".

Google Ngram will find the frequency of words in its db used between 1800 and 2000

The simplest definition would be a common place for free exchanges.

So traffic is different in that while it is an emergent effect of many individual actions, it is not itself a common good, nor are the exchanges particularly volitional. Traffic is something to be avoided, or at least managed in the common interests to minimise the need for the negotiated interactions (like which side of the road to drive on).

And of course the social benefits of free markets is something that the "free marketeers" like to claim for the right. Which is a little ironic.

What makes a fair marketplace is strong regulation - whatever it takes to remove barriers to informed action in the marketplace. The alternative is the rigged market or unlevel playing field. :)

The difference between the market and traffic, is that the former has connotations of persons meeting for an exchange of goods and services. So it exists for a reason or purpose external to itself, not simply as a consequence of other actions, such as the movement of vehicles as is the case with 'traffic'.

(There is, I suppose, the other meaning of 'traffic', as in 'trafficking' - usually applied to contraband - but I don't think this is what you had in mind. I remember when I was a teen, and the band Traffic suddenly became famous - my parents exchanged knowing glances when they heard the name.)

In terms of the ideological importance of the market, surely one of the defining ideas is the idea associated with Adam Smith, 'the invisible hand'. 'The idea of trade and market exchange automatically channeling self-interest toward socially desirable ends is a central justification for the laissez-faire economic philosophy, which lies behind neoclassical economics' (or 'market economics'). This thinking has been profoundly influential on economic theory, hence Reagen's appeal to it.

I think the 'marketplace of ideas' uses the term in a more metaphorical sense.

The exchange of goods and services through the use of money. — Thorongil

The "Longfellow Market" sells groceries in exchange for money.

I don't generally use the term "market" to talk about a "store". To me "market" is a rather abstract term that names large impersonal forces, of the sort that can "freeze up" which is a catastrophe. In 2007 central banks acted to prevent this from happening by creating money. The theory is that if nobody trusted anybody else, an infusion of cash into the system would help. Maybe it did. Some places haven't really recovered 9 years later.

The market is operated by very large institutions and very rich individuals. Not just the stock market, which of course serves institutions and very rich individuals, mostly. But there are other markets: the Chicago Mercantile Exchange (The Merc), Nasdaq, exchanges around the world, and various financial institutions like the World Bank, International Monetary Fund, and so on. There are future markets, and markets on the fluctuating value of currencies.

I don't look at "markets" as some sort of conspiracy (I'll be the last one to find out, most likely) just very big and under no individual's thumb. The markets are everywhere, and in some senses, nowhere, or maybe better, everywhere at once. Markets are like "the climate". Everywhere, subject to influence, not under control.

The market is the exchange of goods and services for money, which includes the process of establishing their prices.

But often in comments and interviews on economy on the news, for instance, 'the market' seems comparable to a medieval use of 'God'. Instead of priests telling us about 'God's will' there are economists or the like telling us what 'the market' demands, or else we will perish. The market is referred to as if it would be an omnipresent creature with its own inscrutable logic.