Origins
The English adjective 'strong' is a fundamental Germanic word whose etymology reveals a surprisingly specific physical image at the core of the concept of strength.βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ It descends from Old English 'strang' (also 'strong'), from Proto-Germanic *strangaz, meaning 'tight, taut, stiff, rigid, severe.' The PIE root is *strenk-, meaning 'tight, narrow, drawn together.' Strength, in the oldest recoverable sense, was not about size or mass but about tension β the tautness of a drawn bowstring, the rigidity of a tightened cord, the stiffness of a tensed muscle.
This etymology connects 'strong' to a family of English words that all carry the idea of tightness and constriction. 'String' (from Old English 'streng,' a cord or rope) is a direct relative β a string is something drawn tight. 'Strangle' (from Latin 'strangulΔre,' from Greek 'strangalΔ,' a halter) shares the same PIE root β to strangle is to tighten something around the throat. 'Stringent' (from Latin 'stringere,' to draw tight) carries the metaphor of tightness into the realm of rules and regulations. Even 'strict' (from Latin 'strictus,' drawn tight) belongs to this family, though it arrived through Latin rather than the Germanic branch.
The Proto-Germanic cognates are illuminating because they have diverged semantically in different directions. While English 'strong' specialized in the meaning of physical power, the cognates in other Germanic languages retained the older sense of tightness and severity. German 'streng' means 'strict, severe, harsh' β a strict teacher, a severe winter. Dutch 'streng' means 'strict, stern.' Swedish 'strΓ€ng' means 'strict, harsh.' Old Norse 'strangr' preserved both meanings, 'strong' and 'severe.' English alone among the major Germanic languages shifted the primary meaning entirely from tightness to power.
Old English Period
In Old English, 'strang' carried both the physical and the metaphorical dimensions of power. It could describe a strong warrior, a strong fortress, a strong wind, or a strong command. The comparative and superlative forms were irregular: 'strengra' (stronger) and 'strengest' (strongest), formed on the variant stem 'streng-' rather than 'strang-.' These forms have been regularized in Modern English to 'stronger' and 'strongest,' but the old stem survives in 'strength' (from Old English 'strengΓΎu'), where the 'e' rather than 'o' vowel preserves the ancient alternation.
The noun 'strength' is formed with the abstract noun suffix '-th' (from Proto-Germanic *-iΓΎΕ), the same suffix found in 'length,' 'width,' 'depth,' 'warmth,' 'growth,' and 'health.' This suffix was highly productive in Old English for forming abstract nouns from adjectives, though it ceased to be productive in later periods. No new '-th' abstractions have been coined in centuries.
The grammatical term 'strong verb' (a verb that forms its past tense by vowel change rather than by adding '-ed,' like 'sing/sang/sung' vs. 'walk/walked') was coined by Jacob Grimm in the early nineteenth century. Grimm chose 'strong' because these verbs form their tenses from internal resources (vowel alternation) rather than relying on external additions (suffixes), and he saw this self-sufficiency as a kind of linguistic strength. The term has no etymological connection to the adjective's original meaning of tautness.
Modern Usage
In modern English, 'strong' has expanded into an enormous range of figurative uses. Strong language (forceful or profane speech), strong tea (concentrated), a strong candidate (formidable), a strong argument (persuasive), a strong suit (an area of excellence, from card games), strong-arm (to use force or intimidation), and going strong (continuing vigorously) all demonstrate the word's metaphorical flexibility. The financial use β a strong dollar, a strong market β dates from the nineteenth century and treats economic vigor as a form of physical power.
The colloquial intensifier 'strong' in phrases like 'a thousand strong' (meaning numbering a thousand) preserves an old adverbial use that dates to Middle English. Here 'strong' modifies a number rather than a noun, functioning as an adverb meaning 'in strength' or 'in number.'
The contrast between 'strong' and 'weak' is one of the primary evaluative oppositions in English, but the two words have very different etymological profiles. While 'strong' has maintained its core meaning (with expansion) for over a millennium, 'weak' was borrowed from Old Norse and originally described something pliant or bendable β the opposite of rigid, which aligns perfectly with the tautness at the heart of 'strong.' The two words are etymological mirror images: strength is tightness, weakness is pliability.