The term "knee-high" refers to a measurement that indicates something reaches up to a person's knee. This height is often used to describe the size of various objects, such as children, plants, or animals. For example, a toddler might be considered knee-high, as they are typically around the same height as an adult's knee. In gardening, "knee-high" can describe the growth stage of certain plants, indicating they are at a manageable height for maintenance. This term is also used in sports, such as football, where players may refer to the height of the ball or other players in relation to their knees.