Concentrative meditation is a whole class of meditation techniques. In most meditation techniques, you are concentrating on one single object. This could be a candle flame, a visualized object, a word or phrase, a chant, the breath and more. When the mind wanders, you just keep going back to your object without judgment.
In mindfulness meditation, you are typically also practicing concentrative meditation. However, when the mind starts taking you away from the object, you calmly watch whatever is happening in the mind before going back to your object.
There's a video below about the art of concentrative meditation, its benefits and how to practice it. Meditation is the art of "falling in love" and concentration is the aspect of meditation that the statement applies to.