English to English Dictionary

Observatory

A room or building housing an astronomical telescope or other scientific equipment for the study of natural phenomena.

Observe

To watch carefully the way something happens or someone behaves.

Observer

A person who watches or notices something.

Observing

Quick to notice things; watchful and alert.

Obsessed

Preoccupied with or dominated by a particular thought or feeling.

Obsession

The state of being besotted with or obsessed by someone or something.

Obsessive

Of or relating to obsession; characterized by or manifesting obsessive behavior.

Obsessive-love

A pathological form of attachment characterized by an overwhelming, intrusive preoccupation with another person, often accompanied by possessive and controlling behaviors.

Obsidian

A dark, glasslike volcanic rock that forms when lava cools rapidly without crystal growth.

Obsolescence

The state of being obsolete or no longer produced or used, or no longer useful.

Obsolescence

The process of becoming obsolete or outdated.

Obsolete

No longer produced or used; out of date.