There are many misconceptions about what spirituality is, some think it is religion, others think it is mysticism or has to do with ghosts etc.
The easiest way to understand spirituality may be to understanding it's opposite, materialism.
Materialism is what makes up the material world and the material life, like eating, sleeping, defending and reproducing and everything related to that is materialism and everything else like philosophy, religion etc is in the field of spirituality.
What makes it confusing is, that for example religion can be material and/or spiritual depending how and for what it is practiced. For example if someone just practices a religion just to get a better reputation or because it makes him money, then this is not or not very spiritual.
So the difference is often hard to understand or hard to grasp and materialistic people may not be able to understand spirituality at all, but I hope the method I presented here helps a bit.