Noun
a skilled worker who can live in underwater installations and participate in scientific research
an underwater swimmer equipped with a face mask and foot fins and either a snorkel or an air cylinder
Source: WordNetPatek Philippe developed a new version of their annual calendar (Ref 5960), but Aquanaut stole the scene celebrating the 20th anniversary with a new 42mm “Jumbo” size (Ref 5168G). Source: Internet