The term weed is used in a variety of senses, generally centering around a plant that is not desired within a certain context. The term weed is a subjective one, without any classification value, since a plant that is a weed in one context is not a weed when growing where it belongs or is wanted. Indeed, a number of plants that many consider "weeds", are often intentionally grown by people in gardens or other cultivated-plant settings. Therefore, a weed is a plant that is considered by the user of the term to be a nuisance. The word commonly is applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More vaguely, "weed" is applied to any plants that grow and reproduce aggressively and invasively. The term weed has also been generalized to any species, not just plants, that can live in diverse environments and reproduce quickly, and the term has even been applied to humans.