There is no 'official' definition of the term macro. It is generally accepted that 'macro' photography starts at a reproduction ratio of 1:1, or 100%. This means the image projected onto the digital sensor or film plane is the same dimension as the actual subject. For example, if you were shooting with a full-frame camera, and your subject measures 24x36mm, it would fill the sensor/film frame. If it didn't the reproduction ratio would be 1:1.5 or 1:2.
If the projected image is larger than the subject, you have RRs of 1.5:1, 2:1 or more depending on the magnification.
Manufacturers tend to play fast and loose with the word macro. Some will call a 1:2 lens a macro. Some sill claim 1:3 is.
Any lens can be used for macrophotography. For the vast majority of them, it would require using additional equipment such as your bellows or extension tubes. Close-up lenses, reversing rings and coupler rings are other pieces of gear that can be utilized.