What exactly is a compost bin/pile? Hey there, so my friend says that her dad is going to...

Hey there, so my friend says that her dad is going to start a compost bin within their backyard, what is a compost bin/pile exactly? I've heard a lot in the region of them lately, sorry if this is a dumb question!
What would you similar to to see at...
Answers:    It's not a dumb question. I in actuality didn't find this out until a couple months ago when my Enviromental Science teacher brought it up. It's a pile of left over or fruitless fruit or veggies, hay, any kind of farm animal waste( chicken, horse, donkey, etc.), grass and possibly a short time bit of dirt from your back yard. Letting adjectives these items sit for about 5-7 weeks causes everything to mix together and break down. Do you know the righteous soil you get form garden stores? Well these items all put into one will brand name this good soil for your plants, or anything that needs to be planted.