Etymology 1 
Three pronunciations can be found in Modern Standard Chinese:
1) Modern dà, from Middle Chinese dɑL, from Old Chinese *daːds. The phonological development from Old Chinese to Middle Chinese is irregular. Original sense: "big" (Shijing). Derived senses: "size" (Mozi), "thick" (Zhuangzi), "to respect" (Mengzi), "to respect" (Xunzi), "to extol" (Gongyang Zhuan), "to exaggerate" (Classic of Rites), "arrogant" (Guoyu), "good" (I Ching), "(of time) long" (Erya), "senior" (Shijing).
2) Modern dài, from Middle Chinese dɑiL, from Old Chinese *daːds. This Middle Chinese pronunciation-preserving (i.e. literary) pronunciation occurs only in compounds such as 大夫 (dàifu, "doctor") and 大王 (dàiwang, "(in operas, old novels) king; ringleader").
3) Modern tài, from Middle Chinese tʰɑiL, from Old Chinese *tʰaːds. This is the ancient form of 太 (tài, "too, excessively") and is obsolete in modern languages.
Pronunciation 2), the diphthong reading, is traditionally regarded as the correct one. However, the monophthong reading 1) has been recorded as early as Han Dynasty, and Sui-Tang rhyme books record both. Both readings are reflected in Sino-xenic readings in non-Sinitic languages, although the diphthong readings dominate in compounds. Axel Schüssler postulates that all pronunciations can eventually be traced back to liquid initials, i.e. 1,2) **laːts, 3) **hlaːts.
The three pronunciations are cognate. Within Chinese, they are cognate with 太 (tài, OC *tʰaːds, "too, excessively"), 泰 (tài, OC *tʰaːds, "big", note that this character also means "to reach", perhaps unrelated), 誕 (dàn, OC *l̥aːnʔ, "big, magniloquent, ridiculous"). There are no unambiguous Tibeto-Burman cognates. Proto-Tibeto-Burman *tay ("big"), from which came Written Tibetan མཐེ་བོ (mthe bo, "thumb"), Nung tʰɛ ("big, large, great"), Mikir tʰè, ketʰè ("id."), Written Burmese တယ် (tai, "very"), is often compared with. There is no final -s in the Tibeto-Burman words, but a -y, which, according to James Matisoff, "indicates emergent quality in stative verbs". Also compare Chinese 多 (duō, OC *ʔl̥aːl, "many, much"), 都 (dū > dōu, OC *taː, "all").
Etymology 2 
Ideogram (指事): a person 人 with arms stretched out as far as possible, implying the meaning of big/great/large. This is in contrast to 小 which represents a person 人 with lowered arms implying small in size.
Compare with 尢, which is a man with bent legs with the meaning of weak.
Compare also 文, which is a man with arms outstretched and a chest or a tattoo on his chest denoting culture or language, and to 夭, which is a man with arms outstretched and leaning to side (running), denoting youth.
|Oracle bone script||Bronze inscriptions||Large seal script||Small seal script|
Han character 
大 (radical 37 大+0, 3 strokes, cangjie input 大 (K), four-corner 40030)
Derived characters 
Related characters 
- KangXi: page 248, character 1
- Dai Kanwa Jiten: character 5831
- Dae Jaweon: page 492, character 25
- Hanyu Da Zidian: volume 1, page 520, character 1
- Unihan data for U+5927
大 (jyutping daai6, Yale daai6)
大 (POJ thài, Guangdong t'ai5; t'ai3 [Meixian, Bao'an], Hagfa Pinyim tai4)
- CCDICT (Chineselanguage.org)
- Academia Sinica - Hakka-English Dictionary
- Lau, Chun-fat. Hakka Pinyin Dictionary (Chinese). Hong Kong: The Chinese University Press, 1997 (Chinese IME supplement) ISBN 962-201-750-9.
- On: だい (dai), たい (tai), た (ta)
- Kun: おお (ō), おおきい (大きい, ōkii), おおいに (大いに, ōini)
- Nanori: うふ (ufu), お (o), おう (ō), た (ta), たかし (takashi), とも (tomo), はじめ (hajime), ひろ (hiro), ひろし (hiroshi), ふとし (futoshi), まさ (masa), まさる (masaru), もと (moto), ゆたか (yutaka), わ (wa)
Usage notes 
This is often the first half two-character shorthand name of universities, for example 東大 (Tokyo University) (“Tōdai”)
- Sound (hangeul): 대 (revised: dae, McCune-Reischauer: tae, Yale: tay)
- Name (hangeul): 크다 (revised: keuda, McCune-Reischauer: k'ŭda, Yale: khuta)
大 (traditional and simplified, Pinyin dà)
Middle Chinese 
Han character 
Min Nan 
大 (POJ tōa (toa7), tāi (tai7))