From page 5 of ‘Far from Land: the Mysterious Lives of Birds’ by Michael Brooke, Pub. Princeton University Press, 2018:
“…The largest seabird group comprises the tube-nosed birds in the order technically known as the Procellariiformes. This order, containing both highly aerial species that feed at the surface and others that are more ore less adept divers, is divided into four families. One family, Diomedeidae, contains the charismatic albatross.”