the way in which a person conducts himself or herself
anything that an organism does involving action and response to stimulation
The simplest behaviour is initiated and controlled by reflexes (input stimuli evoking responses) or by tropisms (movement towards rewarding, or away from noxious, stimuli). Built-in (innate) behaviour can be amazingly elaborate, and appropriate in normal conditions, as for migration or web spinning. Higher animals, especially primates, generalize from past experience to behave with creative intelligence — Professor Richard Gregory
the way in which something, e.g. a machine, functions
behavioural adj
[alteration of Middle English behavour, from behaven: see behave]