Fueng in Thai means 'gear', but I'd imagine that there were star fruit long before there were gears. Star fruit is shaped like a star or gear when sliced cross sectionally. Star fruit is green and tart when unripe. When ripe, the fruit is yellow everywhere except for the edges of the star tips (which are green) and has a sweet mild taste. A star fruit tree can grow as big as an apple tree and it is best to pick them when they are at their peak of ripeness.
With a knife, pare the sharp, still green edges off from the fruit and then cut off the green top and bottom. Slice across the fruit to make stars.