behaviour-n; 2 Senses

Sense Number 1: The action or reaction of something (as a machine or substance) under specified circumstances.

Commentary: BEHAVIOUR[+inanimate][+theme]

The behaviour of small particles can be studied in experiments.
The behaviour of our program is unclear.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: The conduct of a person or organism.

Commentary: BEHAVIOUR[+animate][+agent]

The animal's behaviour cannot be explained by current theories.
Human behaviour is a fascinating object of study.

WordNet 3.0 Sense Numbers: 2, 3, 4