Homeopathy as I know it goes a bit beyond that definition. The basic tenets I usually see are
1. The more you dilute something, the stronger the effects are.
2. Water has memory, so even if there isn't a single molecule of the original substance left in it the above principle still applies.
So most homeopathic medicines are literally just water. They dilute and redilute it until there's no active ingredient left at all.
EDIT: another tenet is "That which would make a healthy person sick makes an unhealthy person well", but doing that would generally be illegal so I don't think mainstream homeopaths follow that one.