What is a forex market?

The foreign exchange market — otherwise called the forex market, or simply the FX market — is the most traded financial market in the world.

More than anything else, the forex market is a trader’s market. It’s a market that’s open around the clock six days a week, enabling traders to act on news and events as they happen, to think about how events can cause the market to go up or down. It’s a market where half-billion-dollar trades can be executed in a matter of seconds and may not even move prices noticeably.
Try buying or selling a half billion of anything in another market and see how prices react.

The Figures
Average daily currency trading volumes exceed $2 trillion per day. That's a huge number isn't it? Just imagine the number of 0s there are.

Liquidity
Liquidity refers to the level of market interest — the level of buying and selling volume — available at any given moment for a particular asset or security. The higher the liquidity, or the deeper the market, the faster and easier it is to buy or sell a security.

A Trading Day
The forex market is open and active 24 hours a day from the start of business hours on Monday morning in the Asia-Pacific time zone straight through to the Friday close of business hours in New York. Or in other words, it is always open. At any given moment, depending on the
time zone, dozens of global financial centers — such as Sydney, Tokyo, or London — are open, and currency trading desks in those financial centers are active in the market.

Currency trading never stops, not even a single day, unlike business which have holidays and such. Even though it’s a holiday in Japan, for example, Sydney, Singapore, and Hong Kong may still be open!

Currencies and Other Financial Markets
As much as we like to think of the forex market as the be all
and end all of financial trading markets, it doesn’t exist in a
vacuum. You may even have heard of some these other markets: gold, oil, stocks, and bonds.
There’s a fair amount of noise and misinformation about the supposed interrelationship among these markets and currencies or individual currency pairs. To be sure, you can always find a correlation between two different markets over some period of time, even if it’s only zero(meaning, the two markets aren’t correlated at all). Always keep in mind that all the various financial markets are markets in their own right and function according to their
own internal dynamics based on data, news, positioning, andsentiment. Will markets occasionally overlap and display varying degrees of correlation? Of course, and it’s always
important to be aware of what’s going on in other financial markets. But it’s also essential to view each market in its own perspective and to trade each market individually.