Pigment is a substance that is so strongly colored that it can be used to change the color of other things too. Pigments are used to tint paint. The best kinds of pigment are ones that are permanent.
Pillars, or columns, are tall, thin posts usually made from stone. Pillars are often decorative, and are usually used for holding something up, like a roof or a bridge.
A pillow is a bag stuffed with something soft. Unlike cushions, pillows are all around the same size. Pillows are for putting your head on when you are asleep at night time. You usually have at least one pillow on your bed.