The question is not silly.
Yarn is packaged and sold in many different forms, the most common forms for hand knitting are...
Balls - look like a round ball
Skeens - similar to a ball but shaped more like a log
Hanks - large loop of yarn that is twisted and folded back onto itself and must be wound into a ball, before it can be used.
Usually the higher quality or hand spun yarns come packaged in hanks. However, don't assume a yarn is high quality simply because it comes in hanks. There are also a great many super high quality yarns that come in balls and skeens.
You may even come across yarns wound onto a roll or cone, although I believe those are designed to be used by a machine, but can also be used for hand knitting.
I ain't goin' on no plane foo!