Solid Agora Cerulean

Latin solidus, firm, dense — used as a color modifier since the seventeenth century for hues that read as continuous and unbroken: a solid blue is one with no variation across the surface. Implies high saturation combined with optical density. Sits in the bold-bucket alongside strong and robust, slightly more focused on uniformity.

Greek agora, Greek-marketplace. As a color modifier, agora implies a Greek-and-Athens-marketplace quality, the visual register of Athenian-and-Spartan-Agora hand-built marketplace-and-civic-meeting-square agora-and-stoa-and-bouleuterion classical-Greek architectural surfaces under Athenian-Agora-and-Spartan-Lacedaemon classical light. Sits at the modifier-and-architecture end of the grid, parallel to forum and stoa in usage.

From the Latin caeruleum, originally referring to dark blue paint pigment of the Roman world, then via French céruléen into English. As a modern art-supply name, cerulean blue is the cobalt-tin oxide pigment introduced in 1805. The color refers to a clean, slightly green-shifted blue with the matte finish of mineral pigment in linseed oil: lighter than cobalt, deeper than aqua, with the painter's weight of a word for sky.