'Rosmarinus' was established as the botanical genus name in modern taxonomy (notably by Carl Linnaeus in 1753) to denote the plant group containing rosemary.

'Rosmarinus' originates from Classical Latin 'ros marinus' (often written as one word 'rosmarinus'), where 'ros' meant 'dew' and 'marinus' meant 'of the sea'; the Latin name referred to the plant we call rosemary.

Initially it literally meant 'dew of the sea'; over time the term became the proper name for the plant rosemary and then the formal scientific genus name 'Rosmarinus'.