There are many traits that can be included to the definition of a learning style, and the answer partly depends on which approach to learning you choose. Educational psychologists tend to put lots of emphasis on motivation (intrinsic vs. extrinsic) and personal attributions (beliefs about self-efficacy), while teachers wish to have concrete tools for helping struggling students. Learning to see things from various points of view is an important skill we should always practice and teach our students, too. So, here you have a short view of three approaches to explain how we actually learn.
At first, learning styles can be seen closely related to learning cycle and the four styles there (converger, diverger, assimilator and accommodator) derived from Kolb's theory of Experiental Learning (and of course also carry the ideas of Piaget with them). Other theorists were further suggesting that we have different preferences where in the cycle we want to start our learning and today the widely accepted styles of Activists, Reflectors, Theorists and Pragmatists are common knowledge.
Yet another quite widely accepted way to identify one's learning "style" is to compare preferences between visual, auditory and kinaesthetic (tactile) intake (VAK). We all have our preferred way of receiving information, and this idea explains how just plain reading or listening a lecture is not the best possible way to learn. The preference how new information is best learned may be any of these three, or any kind of a combination of them, depending on our cognitive structure.
One thing, though, is an absolute fact: each and every student benefits when the information is provided by using at least two of those sensory channels.
Theory of Multiple Intelligences (MI) takes this tri-fold definition pretty much further, but also provides us with practical tools about how to cater for different preferences in the mainstream classroom. While we all have our own personal traits and preferences of reading, seeing, listening, doing, cooperating, reflecting or being impulsive, it is always a good thing to broaden one's preferences.
I would categorize these two last ones (VAK and MI) into teaching strategies, because the "real" learning happens after the intake of information, and must be processed in out brain into higher level knowledge. Of course there are good tools that combine the MI and (revised) Bloom's Taxonomy, providing the practical tools for classroom enrichment.
Yet, I think we should remind educators today about the fact that not all students prefer doing the hands-on activities, and that some students actually DO learn best when they read. After all, learning IS highly individual and happens in our brains, which each are unique, too.