The tea world is as large as it is profound. It has a long history — wars have been fought over it – and a long legacy. It's a beverage that many of us reach for at certain moments of the day.
Black tea accounts for more than 75% of all tea produced worldwide, with green tea accounting for 20% and oolongs, whites, and yellow tea accounting for the remaining 5%. Tisanes, or herbal infusions, such as rooibos tea, mate, rose hip tea, and chamomile tea, have also become popular among tea drinkers around the world. It's crucial to remember, however, that these infusions are not tea because they don't contain any Camellia sinensis leaves.
The literal definition - a non alcoholic oxidized /fermented beverage of leaf buds of a plant “Camellia Sinensis”. It contains tannins which helps in stimulating the appetite. Camellia Sinensis is an evergreen shrub that grows mainly between tropical and subtropical climates. Other major varieties are Assamica or Combodi from Africa.

Origin
Tea was discovered by Shen Nung in 2737 B.C. in China when tea leaves fell down accidently in the boiling water by wind. In India tea was discovered in yr 1824 in the hills along the frontier between Burma and the Indian state of Assam. The Britishers introduced tea culture into India in 1836 and into Ceylon ( Sri Lanka) in 1867. First in India seeds were used from China but later on Assam plant is used.

Herbal Teas/ Tisanes
Teas made by infusion or decoction of herbs, spices, fruits and flowers in hot water are called herbal teas or tisanes. Actually they do not contain any tea leaves (Camellia Sinensis) and no caffeine inside them. If a tea is decaffeinated it does not
mean it is a herbal tea.
Tisanes are refreshing teas without caffeine with lot of antioxidants and have lot of health benefits.