大|だいdai[0]heiban (flat)

1. prefix, na-adjective, nounlarge; big; great; huge; vast; major; important; serious; severe
   この決定けっていはあなたの提案ていあんに負おうところ大だいであった。↗

   Your suggestion weighed heavily in this decision.

   嵐あらしは作物さくもつに大だい損害そんがいを与あたえた。↗

   The storm did great harm to the crop.
2. prefixgreat; prominent; eminent; distinguished
3. suffix-sized; as big as; the size of
   瞬しばたたくうちにテニスボール大だいの団子だんごが消え去きえさった。↗

   In the blink of an eye, the tennis-ball-sized dumpling had disappeared.
4. noun (suffix)university
   彼女かのじょはハーバード大だいに入学にゅうがくした。↗

   She was accepted at Harvard.
5. nounlarge (e.g. serving size); large option
   大だいか、小しょうか。↗

   Large or small?
6. nounlong month (i.e. having 31 days)
7. nounfeces; faeces; excrement; stool

• Synonym大きいおおきいNeutralThe most common adjective for 'big'; it modifies nouns directly, as in 「大きい家」, whereas 「大」 mostly serves as a prefix or appears in phrases like 「大の」 and 「大小」.
• SynonymでかいCasualColloquial and rougher than 「大きい」, as in 「でかい声」; not used in formal settings.
• Synonym巨大きょだいNeutralDescribes extremely large volume or scale, as in 「巨大な建物」; it implies a higher degree than 「大」 and appears mostly in written description.
• SynonymおっきいCasualA colloquial sound variant of 「大きい」 with a casual feel; it can sometimes come across as cute.
• Synonym大型おおがたNeutralCovers large size or model type, as in 「大型トラック」 and 「大型台風」; often used for classification, the counterpart of 「小型」.
• SynonymどでかいCasualColloquial: stresses that something is astonishingly big, with a stronger, more exaggerated tone than 「でかい」.
• Synonym馬鹿でかいばかでかいCasualColloquial for absurdly large, often with surprise or a negative shade, as in 「馬鹿でかい家」; avoid it in formal settings.
• Related膨大ぼうだいWrittenA written word for vast quantity or scale; it typically modifies things like data or expenses, as in 「膨大なデータ」, stressing sheer volume.
• Related大規模だいきぼNeutralMeans large in scale, as in 「大規模な工事」 and 「大規模な災害」; the counterpart of 「小規模」.
• Related多額たがくNeutralRefers to large amounts of money, as in 「多額の借金」; it applies only to sums of money.
• Related過大かだいNeutralIndicates something exceeds an appropriate degree, as in 「過大評価」 and 「過大な期待」; it implies excess, a nuance 「大」 does not have.
• Related多量たりょうNeutralMeans a large quantity, as in 「多量の水」; it stresses amount, contrasts with 「少量」, and leans toward written style.
• Related大々的だいだいてきNeutralDescribes grand, high-profile scale, as in 「大々的に宣伝する」; it usually modifies events or publicity and is often used adverbially.
• Related極大きょくだいWrittenA written term for 'extremely large'; in mathematics it denotes a local maximum, the opposite of 「極小」. Mostly an academic term.
• Antonym小しょうNeutralThe antonym for 'small'; it contrasts with 「大」 in size or specification, as in 「大中小」.
• Antonym微びWrittenA written prefix for extremely minute things, as in 「微生物」 and 「微増」; it sits at the opposite end of the size scale from 「大」.

Use 「大」 as a prefix or in set phrases like 「大の」 and 「大小」; to state that something is big, the default is 「大きい」, with 「でかい」 in casual speech. For extreme size or scale pick 「巨大」, for large-scale projects 「大規模」 or 「大型」, and for huge quantities 「膨大」.

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

1. （ダイ）おおきいこと。
2. （ダイ）一人前いちにんまえのおとなであること。
3. （ダイ）程度ていどがはなはだしいこと。
4. （ダイ）巨大きょだい。
5. （ダイ）偉大いだい。
6. （ダイ）親子関係おやこかんけいを持もつ二人ふたりの人物じんぶつのうち、親おやの方ほう。
7. （ダイ）その大おおきさ。
8. （ダイ）大学だいがく。