Salience
The property of being noticeable or important — i.e. the perceptual quality by which an observable thing stands out relative to its environment.
Origin
The word derives from the Latin salire, meaning "to leap." In English, salient carried the sense of "projecting" as early as the 15th century, and by the 17th century had evolved to mean "conspicuous." The technical sense in cognitive science and psychology crystallized through the mid-20th century, as researchers studying attention needed precise language for what causes certain stimuli to stand out over others. William James addressed related ideas in his 1890 Principles of Psychology, and the term became foundational in later computational models of visual saliency developed from the 1980s onward.