An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Forming a whole; of or characteristic of a group taken together.

→ collect + → -ive.

1) The whole behavior of a system of many interacting components, which differs from that of the individual components. Some classical examples are the → many-body problem, → phase transition, most of thermodynamic phenomena, collective oscillations occurring in solids, etc. Physics dealt with collective behavior much earlier than the term collective behavior was even coined.
2) Sociology: The more or less unpredictable act of people when being in group, which is totally different from the behavior they would have if acted individually.
3) Biology: A large number of group phenomena such as pattern formation, self organization, trail formation, and synchronization seen among many living creatures.

→ collective; → behavior.

Formation of stars, especially → massive stars, in group as opposed to individual formation.

→ collective; → star; → formation.