Traditionally, many people who rode horses also carried weapons and tools, since horses were used as working animals. Swords tended to be worn on the left side, as did other weapons, so people mounted their horses from the left to ensure that their swords did not bang into the horse while they were mounting. This was especially critical in the days before stirrups, when the rider had to basically vault into the saddle. If people mounted on the off side, their swords would have dragged across the back of the horse while the left leg was being swung into place, upsetting the horse and potentially causing it to bolt.

If olive oil is made of olives, what is baby oil made of OMG.

Why isn't a fortnight a fourtnight?

A fortnight sounds like an evening on guard along the bastions.

And why don't Americans use the word "fortnight." It's a good one .

What did we go back to before we invented the drawing board?