永代|えいたいeitai[0]heiban (flat)

1. nounpermanence; eternity

• Synonym永遠えいえんNeutralThe most general word for eternity; can act as a na-noun, as in 「永遠に続く」. 「永代」 is mostly a compound element for permanence across generations, as in 「永代供養」.
• Synonym永久えいきゅうNeutralStresses unbroken continuation from a point in time (「永久保存」, 「永久歯」); common in daily use. 「永代」 points to generational succession, as in temple and land-rights terms.
• Synonym恒久こうきゅうWrittenStresses being long unchanged and stable, as in 「恒久平和」 and 「恒久的な対策」; written style, common in policy documents. 「永代」 instead stresses permanence across generations.
• Synonym永世えいせいWrittenMeans permanent and unchanging, as in 「永世中立」; also a lifetime title in shogi or go, as in 「永世名人」. 「永代」 typically pairs with memorial services and usage rights.
• Synonym長久ちょうきゅうWrittenMeans lasting long, mostly in well-wishing phrases like 「武運長久」, with a prayer-like flavor. 「永代」 instead concerns generational rights or memorial services.
• Synonym悠久ゆうきゅうWrittenStresses a long, unbroken sweep of history, as in 「悠久の歴史」, looking back from the past to the present. 「永代」 looks ahead to future generations.
• Synonym永劫えいごうWrittenAn immensely long, endless span of time with a Buddhist coloring; mostly seen in 「未来永劫」. 「永代」 is the practical, generational term.
• Synonym久遠くおんWrittenSolemn and lofty, for the immensely remote past or future. 「永代」 looks only at continuation into future generations.
• Synonym無窮むきゅうWrittenMajestic in tone; can describe endlessness of space as well as time. 「永代」 covers only generational permanence in time.
• Synonym未来永劫みらいえいごうWrittenA four-character phrase, also usable adverbially, stressing forever from now on, as in 「未来永劫変わらない」. 「永代」 mostly forms compounds as a noun.
• Related千代ちよWrittenAn archaic, elegant word for a thousand years, as in the anthem line 「千代に八千代に」 and birthday felicitations. 「永代」 is a modern practical term.
• Related万世ばんせいWrittenThe same word as 「万代」 above, in the variant writing 「万世」, likewise celebratory in tone. For everyday talk of permanence, 「永遠」 or 「永久」 will do.
• Related万代ばんだいWrittenFor all generations to come, with a celebratory, well-wishing tone; can also work as an adverb. 「永代」 mostly heads compounds for memorial services, usage rights, etc.
• Related生々世々しょうじょうせぜWrittenOriginally Buddhist, for every life in the cycle of rebirth; rarely used today. 「永代」 remains a practical term for generational permanence.
• Related永久とわNeutralStresses unbroken continuation from a point in time (「永久保存」, 「永久歯」); common in daily use. 「永代」 points to generational succession, as in temple and land-rights terms.
• Related常世とこよWrittenAn old word for eternal unchangingness, also for the mythical land of 「常世国」 or the world of the dead. 「永代」 is modern and practical, with no such extensions.
• Related千古せんこWrittenCan mean the remote past as well as eternity, as in 「千古の謎」, with an eye from antiquity to today. 「永代」 looks to the generations ahead.
• Related万古ばんこWrittenFor what has held unchanged since remotest antiquity, as in 「万古不易」; looks from the past onward. 「永代」 looks to transmission into future generations.
• Related万劫ばんごうWrittenA Buddhist term for an extravagantly long stretch of time; rarely used alone today. 「永代」 still appears in practical contexts like memorial services and land rights.
• RelatedエタニティNeutralA loanword for eternity, mostly in jewelry and product names, as in 「エタニティリング」. Ordinary prose prefers 「永遠」; 「永代」 stays with generational permanence.
• Related万劫末代まんごうまつだいWrittenAn exaggerated four-character phrase, usable adverbially, for endless generations upon generations; rare today. In everyday speech just say 「永遠に」.
• AntonymひとときNeutralA short while or moment, as in 「楽しいひと時」; the opposite of 「永代」 in sheer length of time.

Use 「永代」 for permanence passed down through generations; it mostly appears as the first element of compounds like 「永代供養」 and 「永代使用権」. For everyday 'forever', use 「永遠」 or 「永久」; for a long, unbroken history, 「悠久」. The many written terms (「恒久」「永世」「長久」「永劫」「久遠」「無窮」「未来永劫」「万代」「千代」 and the rest) suit solemn, celebratory or religious prose, while エタニティ turns up in jewelry and product names. The antonym is 「ひと時」, a brief moment.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 長ながい間あいだ。永世えいせい。永久えいきゅう。