hardens

Hardens is the third-person singular present tense of the verb harden. The core meaning is to cause something to become hard or to become hard itself, and it is used across many domains to describe processes that increase rigidity, strength, or resistance, as well as natural changes that lead to a harder state. The term can also be used metaphorically to indicate increased firmness of rules, policies, or attitudes.

In materials science and construction, hardening refers to processes that raise hardness, such as curing, heat treatment, or chemical cross-linking. Concrete hardens as cement hydrates; steel can be hardened by heat treatment; plastics may harden through cross-linking. In cooking and food preparation, substances like sugars, chocolates, or doughs may harden as they cool or dry, forming a solid exterior or structure. In daily language, people may say a surface has hardened, meaning it has become less malleable or more resistant to deformation.

In information technology and cybersecurity, to harden a system means to reduce its vulnerability by applying stricter configurations, patches, and controls. Security hardening is a common practice in securing operating systems, networks, and applications, often accompanied by standardized guidelines and checklists.

Etymologically, hardens derives from the adjective hard with the a verb-forming suffix -en, reflecting its long-standing use in English to indicate a transition to a harder state. Related terms include hardness, hardening, and to harden (infinitive).