You're right that it's about a space, or a field, which is in the name, but you're wrong in contradicting the other poster. The near field is determined by the radiating surface, the front baffle of the speaker. Room height line arrays for example have a large near field. Near field speakers are those with tuning designed to be flattest when listened to inside the near field. The link you posted is confused and misleading, which is unfortunate since they dressed it up as some kind of "myth busting".