What is the meaning of Liquidus?

A line, in a phase diagram, above which a given substance is a stable liquid and below which solid and liquid are in equilibrium.

liquid, fluid, flowing

clear, transparent, limpid

without interruption, smooth, fluid, flowing

clear, calm, serene, peaceful

unadulterated, unmixed, pure

clear, manifest, evident, obvious, certain

Source: wiktionary.org