solidity
UK: /səˈlɪd.ə.ti/ | US: /səˈlɪd.ə.ti/
n. the quality or state of being solid; firmness or hardness
n. (figurative) the quality of being reliable, substantial, or logically sound
The word "solidity" derives from the Latin solidus (meaning "firm, whole, dense"), combined with the suffix -ity, which forms abstract nouns denoting a state or condition. The root "solid" has retained its core meaning of physical firmness, while the suffix "-ity" systematically transforms adjectives into nouns (e.g., "purity" from "pure"). Over time, "solidity" expanded beyond physical hardness to describe abstract reliability or logical coherence, reflecting the metaphorical extension of "solid" as "strong" or "trustworthy."
The solidity of the ancient stone bridge impressed the engineers.
Her argument lacked solidity, as it was based on assumptions rather than evidence.
The artist emphasized the solidity of the sculpture by using heavy materials.
Financial stability adds solidity to a business during economic downturns.
Scientists tested the solidity of the new alloy under extreme pressure.