Ephemerality (from the Greek word ἐφήμερος, meaning 'lasting only one day'[2]) is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, from digital media to types of streams.[3] "There is no single definition of ephemerality".[4] With respect to unique performances, for example, it has been noted that "[e]phemerality is a quality caused by the ebb and flow of the crowd's concentration on the performance and a reflection of the nostalgic character of specific performances".[5] Because different people may value the passage of time differently, ephemerality may be a relative, perceptual concept: "In brief, what is short-lived may not be the object itself, but the attention we afford it".[6][7]