The term 'mint' has two main meanings. First it is used to refer to the entire family Lamiaceae; secondly it is used for the aromatic Mentha genera within this family.
The Lamiaceae are native to most parts of the world, and contain 236 genera and approximately 7000 species. Members are frequently aromatic, and are commonly used as culinary herbs. In addition to herbs such as basil, mint, rosemary, sage, marjoram, and oregano; the Lamiaceae also include some shrubs, and trees (e.g. teak). They are generally easy to cultivate, and are hence in widespread cultivation.
Lamiaceae have opposite leaves. Some sources describe "square stems" as a diagnostic feature although this is not always the case, and other plants may have square stems. Flowers are bilaterally symmetrical with 5 united petals and 5 united sepals.
Although the mint tag could be used for all Lamiaceae (ie. the botanical sense), it should only be used for the Mentha genera - "mints" in the horticultural and culinary sense. Mentha consist of between 13 and 18 species - definitions are not distinct and are complicated by hybridization and cultivars. Mentha mints are aromatic, perennial (although sometimes annual), and are all grown as herbs.