What shark family is commonly called the requiem sharks?

The shark family commonly called the requiem sharks is Carcharhinidae.

Carcharhinidae is a family of warm-water sharks within the order Carcharhiniformes. It includes familiar species such as the blacktip shark, bull shark, lemon shark, oceanic whitetip shark, and several reef sharks. Requiem sharks are generally migratory and live-bearing: females give birth to fully developed young rather than releasing eggs.

“Requiem shark” describes a family, not one species. The group ranges greatly in size, from the roughly 69-centimetre adult Australian sharpnose shark to the oceanic whitetip shark, which can reach about 4 metres. The name’s origin is uncertain; it may relate to the French word requin, meaning shark, or to older French etymology.

A common mix-up is treating every large predatory shark as a requiem shark. Tiger sharks, for instance, are traditionally placed in their own family, Galeocerdonidae, even though they share the same broader shark order.