As a rule of thumb, you can determine if a trim is braided by process of elimination. If it’s not leather, not fringe, not sequin and not pleated fabric, it’s probably a braid of some kind or other.
Most often, you’ll find this on costumes with a military flavor – officers love fancying up their dress uniforms with braid. It will turn up on certain folk costumes, too, as braiding strands of something is a task that even a peasant can do without any other tools.
The washability of braided trim depends on what its made from – pay attention to the spool when you buy it. The most common varieties are made from polyester and are okay to wash in a machine, unless they’re metallic in which case, they might be hand-washable, but you don’t want them going anywhere near your dryer.