乳

乳 (Kangxi radical 5, 乙+7, 8 strokes, cangjie input 月木山 (BDU), four-corner 2241₀, composition ⿰孚乚)

• 啂 㳶 𡝦 𥯇

• Kangxi Dictionary: page 84, character 17
• Dai Kanwa Jiten: character 190
• Dae Jaweon: page 171, character 22
• Hanyu Da Zidian (first edition): volume 1, page 55, character 4
• Unihan data for U+4E73

Historical forms of the character 乳
Shang	Shuowen Jiezi (compiled in Han)	Liushutong (compiled in Ming)
Oracle bone script	Small seal script	Transcribed ancient scripts
Oracle bone script j25390 Small seal script s08669 Transcribed ancient scripts L34366 L14508 L14509 L14510 L14511
References: Mostly from Richard Sears' Chinese Etymology site (authorisation), which in turn draws data from various collections of ancient forms of Chinese characters, including: Shuowen Jiezi (small seal), Jinwen Bian (bronze inscriptions), Liushutong (Liushutong characters) and Yinxu Jiaguwen Bian (oracle bone script).

Pictogram (象形) : A woman breastfeeding a child.

From Proto-Sino-Tibetan *s-nəw.

乳

1. (literary) to breastfeed; to suckle
2. breast; nipples
3. milk; breast milk

   母乳  ―  mǔrǔ  ―  breast milk; mother's milk

   水乳交融  ―  shuǐrǔjiāoróng  ―  to get along well

4. milk- or cheese-like substance
5. newborn; young and small

   乳豬／乳猪  ―  rǔzhū  ―  suckling pig

6. to multiply; to proliferate; to reproduce; to breed

• (to breastfeed):

• (breast):

• (milk):

• (young and small): 幼小 (yòuxiǎo)
• (to multiply):

(grade 6 “Kyōiku” kanji)

• Go-on: にゅう (nyū, Jōyō)
• Kan-on: じゅ (ju)^{←じゆ (zyu, historical)}
• Kun: ち (chi, 乳, Jōyō); ちち (chichi, 乳, Jōyō)
• Nanori: ち (chi)

• (Tokyo) ちち​ [chìchíꜜ] (Odaka – [2])[2][3]
• (Tokyo) ち​ち [chíꜜchì] (Atamadaka – [1])[2][3]
• IPA^(key): [t͡ɕi̥t͡ɕi]

乳(ちち) • (chichi) 

1. (dated) milk
2. breast (of a woman, of a female mammal)

• お乳(ちち) (ochichi, “milk”)
• おっぱい (oppai, “milk, breast”)
• 乳(ち)房(ぶさ) (chibusa, “breast”)
• 胸(むね) (mune, “breast”)

• 上(うえ)乳(ちち) (uechichi): the upper part of a woman's breast
• お乳(ちち) (ochichi): milk
• 下(した)乳(ちち) (shitachichi): the underside of a woman's breast
• 乳(ちち)搾(しぼ)り (chichishibori)
• 乳茸(チチタケ) (chichitake): milk-cap mushroom

• → Korean: 찌찌 (jjijji)

• (Tokyo) ち​ [chíꜜ] (Atamadaka – [1])[2][3]
• IPA^(key): [t͡ɕi]

乳(ち) • (chi) 

1. (archaic) milk
2. (archaic) breast

• 乳(ち)兄(きょう)弟(だい) (chikyōdai)
• 乳(ち)飲(の)み子(ご) (chinomigo)
• 乳(ち)房(ぶさ) (chibusa)

From Middle Chinese 乳 (MC nyuX).

• (SK Standard/Seoul) IPA^(key): [ju]
• Phonetic hangul: [유]

Wikisource 乳 (eumhun 젖 유 (jeot yu))

1. Hanja form^? of 유 (“breast”).
2. Hanja form^? of 유 (“milk”).

• 국제퇴계학회 대구경북지부 (國際退溪學會 大邱慶北支部) (2007). Digital Hanja Dictionary, 전자사전／電子字典.

乳: Hán Việt readings: nhũ[1][2][3]
乳: Nôm readings: vú[1][3][4], nhỏ[1][2], nhủ[1][2], nhũ[2][4], nhả[2], nhỗ[3], nhú[5]

1. chữ Hán form of nhũ (“breast”).
2. Nôm form of vú (“breast”).