古英語seofonから、原ゲルマン語*sebunから、PIE*septm, sevenから、語源はSeptember, septetと同じ。
FOOL: ... The reason why the
seven stars are no more than seven is a pretty reason.
LEAR: Because they are not eight?
FOOL: Yes, indeed: thou wouldst make a good fool.
["King Lear," I.v.]