Seven — From Proto-Indo-European to English | etymologist.ai
seven
/ˈsɛv.ən/·numeral·c. 1500 BCE in Vedic Sanskrit (saptá, Rigveda); Old English seofon attested from c. 8th century CE; PIE *septḿ̥ reconstructed to c. 4500–2500 BCE.·Established
Origin
From PIE *septḿ̥, 'seven' reachesEnglish three ways: natively as 'seven', through Greek as 'hepta-' (heptagon), and through Latin as 'sept-' (September). Septemberwas the 7th month in Rome's original 10-month calendar — the name outlasted the reform that made it the 9th.
Definition
The cardinal number equal to six plus one, descending from Proto-Indo-European *septḿ̥, preserved across nearly all Indo-European branches.
The Full Story
Proto-Indo-Europeanc. 4500–2500 BCEwell-attested
PIE *septḿ̥ is one of the most stable inherited numerals in the Indo-European family, attested across every major branch without exception. The form is syllabic, with the final *-m̥ functioning as a syllabic nasal — a feature preserved in Sanskrit saptá and Avestan hapta. The numeral may encode an archaic counting structure: some historical linguists propose that *septḿ̥ reflects an additive compound conceiving
Did you know?
September, October, November, and December are etymologically the 7th, 8th, 9th, and 10th months — because the original Roman calendar started in March and had only ten months. When January and February were added to the front, the month names became permanently wrong by two positions, and have stayed that way for roughly 2,700 years. Every timeyou write a September
in March. When January and February were inserted under Numa Pompilius, the ordinal names of September through December became permanently misaligned by two positions — a fossil of the original count that survives in the modern calendar. Greek ἑπτά (heptá) generated the productive prefix hepta- in heptagon and heptathlon. The numeral's ritual salience — seven planets visible to the naked eye, seven days of the week, seven deadly sins — likely reinforced its stability across millennia. Key roots: *septḿ̥ (Proto-Indo-European: "seven — syllabic-nasal form, ancestral to all IE branches"), *sebun (Proto-Germanic: "seven — post-Grimm's Law form, ancestor of Gothic sibun, OE seofon, German sieben"), septem (Latin: "seven — source of September, septet, septennial, septuagenarian"), hepta (ἑπτά) (Ancient Greek: "seven — base of hepta- compounds: heptagon, heptathlon").
septem(Latin (true cognate from PIE *septḿ̥))hepta (ἑπτά)(Ancient Greek (true cognate from PIE *septḿ̥))saptá(Sanskrit (true cognate from PIE *septḿ̥))sem' (семь)(Russian (true cognate from PIE *septḿ̥))septyni(Lithuanian (true cognate from PIE *septḿ̥))sieben(German (true cognate from PIE *septḿ̥ via Proto-Germanic *sebun))