What does it mean if you have double vision? is this a neurological condition?

Possibly: There are many causes of double vision. The most concerning is neurological disorders, like a stroke. Only your ophthalmologist can determine the cause of your double vision. If you have double vision you should consult your ophthalmologist immediately, as there are some life-threatening conditions that can cause double vision.

Maybe: By definition, your eyes are crossing either horizontally/vertically or both. This can be from injury, strokes, diabetes, illness/tiredness and may be temporary or permanent. It should be checked by your eye doctor.

Can be: Binocular double vision typically indicates an eye alignment issue, which can be neurological (vascular, hemorrhagic event or mass), mechanical in terms of affecting the extraocular muscles motility, neurologic in terms of the nerve input to the muscles.