First of all- What is Tea?

Basically is Tea a plant. Everthing which is called Tea,comes from the same leafes of the plant, Camellia sinensis.It doesn't matter if the tea is green, white tea, oolong or black tea, which are the most common teas found on the market.The difference of the tea type is the processing and the harvest of the leaves.
But it would be techinally wrong to say herbal teas, fruit teas or rooibos tea, because they are no real teas, but today nobody really makes a difference between them. But as long as somthing is brewed out of fruit, leaves, barks, roots or something like those it is called tea.
After water, tea is the most worldwide-consumed drink on the world.

Where does Tea come from?

Tea was first brought to Europe by Dutch traders, who came into cantact with the trough Chinese traders in Java, who came from the southern part of Amoy, which is Xiamen today. In Chinese Tee means Cha, but all the other European countries, with an exaption of Portugal and Russia bought the name for the Tea from the Dutch. So in most of the European languages the word for Tea is pretty similar.
With the Overland the Tea came to all the other parts of the world.
Thats the explaning why the Expression "a cup of Cha" is still use in Britain and Ireland. It seems to go back to the beginnings.