isolation

Isolation refers to the condition of being separated from others or from a surrounding environment, resulting in limited contact, interaction, or exchange. The concept is used in everyday language and in specialized fields to describe different forms of separation, from physical barriers to social deprivation.

In social and psychological contexts, social isolation describes a lack of meaningful social connections or engagement. It can be voluntary or involuntary and is linked with adverse health outcomes, including increased risk of depression, cardiovascular disease, and mortality, especially among older adults.

In biology, geographic isolation occurs when physical barriers such as mountains or water bodies prevent gene flow between populations, facilitating divergent evolution. Reproductive isolation mechanisms—prezygotic and postzygotic—reduce or prevent interbreeding and contribute to speciation.

In medicine and public health, isolation is the separation of individuals who are infected or suspected of infection to prevent transmission. Practices include various levels such as contact, droplet, and airborne isolation, and may involve quarantine for exposed but asymptomatic people. Facilities, personal protective equipment, and protocols are used to enforce it.

In science and engineering, isolation also denotes the separation of systems or components to prevent interference or hazard. Electrical isolation uses insulators or isolation transformers to prevent current flow; optical isolation uses light signals. In computing, database transaction isolation levels describe how and when changes by concurrent transactions become visible, ranging from read uncommitted to serializable.