armor-piercing

The compound adjective "armor-piercing" is a modern, transparent formation from two English words of distinct origins. "Armor" traces back to Latin armatura, denoting military equipment, while "pierce" entered English via Old French with a core meaning of making a hole. The logic of the compound is purely functional and descriptive, combining the object ("armor") with the intended action ("piercing") to create a technical term. It emerged in the late 19th to early 20th century alongside advancements in military technology, specifically to describe ammunition and weapons designed to defeat armored vehicles and fortifications. There is no ancient metaphorical evolution; the term's meaning is directly literal, built from the contemporary senses of its constituent parts.

Structure: armor (protective covering) + piercing (penetrating) - armor: From Old French armeure, ultimately from Latin armatura (equipment, arms), from armare (to arm). In this compound, it functions as a noun specifying the target. - piercing: From the present participle of the verb pierce, from Old French percer, possibly from Latin pertusiare (to bore through). In this compound, it functions as an adjective describing the action or capability.