case closed by my father

It's a way of cutting things up. Study your textbook for more examples.

There is more than five. Julienne, roundel, dice, chiffonade paysanne that's five

They should be green.

Actually- the red and purple ones are really good for you. Have a look at the bottom where they were cut away from the plant. If it's brown and slimy then put them back.

"Julienne" cuts are thin strips. Cutting julienne carrots would mean slicing the carrot on the long side into strips that are about 1/8" thick. Then, lay the strips down and cut them again so you're left with many little 1/8" x 1/8" thick carrot sticks. The benefit is that they cook very quickly, retaining color, texture and fresh flavor.