What is Market System?

Legal Definition
A market system is any systematic process enabling many market players to bid and ask: helping bidders and sellers interact and make deals. It is not just the price mechanism but the entire system of regulation, qualification, credentials, reputations and clearing that surrounds that mechanism and makes it operate in a social context.

Because a market system relies on the assumption that players are constantly involved and unequally enabled, a market system is distinguished specifically from a voting system where candidates seek the support of voters on a less regular basis. However, the interactions between market and voting systems are an important aspect of political economy, and some argue they are hard to differentiate, e.g. systems like cumulative voting and runoff voting involve a degree of market-like bargaining and trade-off, rather than simple statements of choice.
-- Wikipedia
Legal Definition
Permitted interaction between buyers and sellers as this social network. Rules, regulations, and involved entities' reputations and credentials are included. Market players bid and ask within the market system. Several types of market systems currently exist: Auctions, rationing, black market, free market, real estate market, stock market, and the like.