Of or regarding Laurentius or Lorenzo dei Medici, or even to the Laurentian Library in Florence, named from him.
Of or related to the river St. Lawrence: applied in geology, in 1854, by Sir W. E. Logan, to a few rocks occupying an extensive area around top of the Lakes, and formerly known as by him the metamorphic series, and by Foster and Whitney the azoic show.
How would you define Laurentian?