Defining Caviar Caviar, in its truest definition, refers to the salt-cured eggs (roe) of sturgeon fish. While the term is sometimes loosely applied to the roe of other fish — salmon, trout, or lumpfish — purists and international food regulations reserve the word "caviar" exclusively for sturgeon roe. This distinction matters because the unique characteristics of sturgeon roe — the delicate pearl structure, the complex flavour, the luxurious mouth-feel — are what have made caviar the world's most prestigious food for centuries. Sturgeon are ancient fish, belonging to a family (Acipenseridae) t