Ephemeral things (from Greek εφήμερος - ephemeros, literally "lasting only one day) are transitory, existing only briefly. Typically the term is used to describe objects found in nature, although it can describe a wide range of things.
An ephemeral waterbody is a wetland, spring, stream, river, pond or lake that only exists for a short period following precipitation or snowmelt. They are not the same as intermittent or seasonal waterbodies, which exist for longer periods, but not all year round.
Examples of ephemeral streams are the Ugab River in Southern Africa, and a number of small ephemeral watercourses that drain Talak in northern Niger. Other notable ephemeral rivers include the Todd River and Sandover River in Central Australia as well as the Son River, Batha River and the Trabancos River.
Many plants are adapted to an ephemeral lifestyle, in which they spend most of the year or longer as seeds before conditions are right for a brief period of growth and reproduction. The spring ephemeral plant mouse-ear cress is a well known example. Animals can be ephemeral, with brine shrimp being an example.
Ephemeral can also be used as an adjective to refer to a fast-deteriorating importance or temporary nature of an object to a person. Brands are notoriously ephemeral assets, and magazine publishing was once much more ephemeral than it is today.
A number of art forms can be considered ephemeral because of their temporary nature. Early land art and all sand sculptures, ice sculptures and chalk drawings on footpaths are examples of ephemeral art. G. Augustine Lynas and Duthain Dealbh create ephemeral sculptures.
A sensation which is felt by a person for a certain period of time before needing replenishment can be referred to as ephemeral. Often, happiness is described as ephemeral, as one does not find it as a permanent state, with human lives always varying shades of happiness and disappointment.