How do you pronounce ephemeral?

Four syllables: ih-FEM-er-ul. The stress falls on the second syllable, with a short 'e' as in 'gem'. The 'ph' is a simple 'f' sound, a souvenir from the Greek phi. American and British pronunciations are essentially identical, although speakers in Britain often clip the final two syllables into a near-schwa.

Is ephemeral the same as temporary?

They overlap, but the connotation differs. Temporary is neutral and administrative: a temporary password, a temporary repair. Ephemeral is descriptive and slightly elegiac: it suggests that the brevity is part of what matters. A scaffold is temporary; a sunset is ephemeral. Using ephemeral for something purely functional usually sounds overwrought.

Can people be ephemeral?

In poetry, yes; in everyday speech, rarely. You can describe an ephemeral mood, an ephemeral celebrity, or even an ephemeral generation, but calling a person ephemeral can sound either bleakly philosophical or a little cruel. Most writers reserve it for moments, sensations, weather, fashions and small natural events.

What is the noun form?

There are two. 'Ephemerality' is the abstract quality of being short-lived, used in essays and academic writing. 'Ephemera' (used as a plural noun) refers to printed objects that were never meant to last: tickets, posters, pamphlets, takeaway menus. Confusingly, the singular ephemeron exists for a single such item, but it is rare outside collectors' circles.