Cha means tea and it usually refers to green tea in Japan. As we all know, the leaves of a type of Camelia plant in China spread to the world together with its name. Green tea was introduced to Japan by Buddhist priests and had been medicinal long before common people enjoyed it as a drink.
Before people started to enjoy steeped leaf tea, matcha, ground tea leaves, had been used and is still used for the tea ceremony and matcha ice cream. Yes, the latter is very popular with the combination of bitter and sweet. It is easy to make: thaw some vanilla ice cream and mix the tea powder before freezing it again. Or just sprinkle some as a topping.
I belonged to the tea ceremony club at high school, and though I appreciated the rice cake before the tea, the formal manners and rules were a bit too much for me, let alone sitting on my knees. I got the basic idea though, and can whisk powder tea in the tea bowl properly. My daughter enjoys it too, after taking some lessons at her primary school. We make sure to visit a tea house when we travel. Tea houses are beautiful and calming, and these days people are not too worried about traditional formality. You can get the service, tea and cake for around ¥500, while enjoying the quiet and relaxing atmosphere, often looking out over a garden.