A reference is something you look at to inspire your own art, and possibly draw direct elements from. It may be a photo, a sculpture or anything from the real world. Everything you draw is based on a reference, even if that reference is based on a memory, as drawing itself is a way of copying the reality. Using a reference in the moment of drawing highly increases your learning speed.
Jerome Okutho's insight:
Looking to level up your digital artwork? It turns out referencing is a really effective way to improve your work, and make it more creative. So what exactly is referencing and how can it help you?