Habit, when used in the context of biology, refers to the instinctive actions of animals and the natural tendencies of plants.
In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology. For example:
In botany, the term is used most often to describe the general appearance, growth form, or architecture of a plant. For example:
Since both concepts – mode of behavior and external form – are significant in zoology, the term habitus (from which the word "habit" actually derives) is used for the latter. Habitus may also be found in botany; here it means the same as "habit", as plants generally do not have "habits" in the zoological sense.