In context, the Swedish word "ballad" is a subtype of "visa" that tells a story in many verses, similar to the medieval ballads, as opposed to for instance lyrical songs about the beauty of nature. The Swedish ballads can be performed to a big orchestra but are often sung to fairly simple accompaniment on guitar, or other instruments such as piano or accordion.
In context, the Swedish word "ballad" is a specific kind of "visa," which tells stories in multiple verses, like medieval ballads. Unlike lyrical songs focused on nature's beauty, Swedish ballads can be performed with large orchestras but are often sung with simple guitar accompaniment or other instruments like piano or accordion.