約

約 (Kangxi radical 120, 糸+3, 9 strokes, cangjie input 女火心戈 (VFPI) or 女火心一 (VFPM), four-corner 2792₀, composition ⿰糹勺)

• 喲(哟), 𡟅, 𢰹, 𤋢, 𧎒, 𧼿, 葯(药), 𦋥, 𦋩, 箹(𰩺)

• Kangxi Dictionary: page 915, character 21
• Dai Kanwa Jiten: character 27242
• Dae Jaweon: page 1343, character 7
• Hanyu Da Zidian (first edition): volume 5, page 3364, character 15
• Unihan data for U+7D04

Historical forms of the character 約
Warring States	Shuowen Jiezi (compiled in Han)	Liushutong (compiled in Ming)
Chu slip and silk script	Small seal script	Transcribed ancient scripts

Phono-semantic compound (形聲／形声, OC *ʔlewɢs, *ʔlewɢ) : semantic 糸 (“rope”) + phonetic 勺 (OC *pljewɢ, *bljewɢ).

約

1. ^† to bundle up; to bind
2. ^† rope; cord
3. ^† to restrain; to limit; to keep under control
4. to make an appointment; to arrange
5. appointment; meeting; arrangement
6. treaty; agreement; covenant; pact; contract
7. to invite or ask in advance

   我想約你明天一起去吃飯，不知道你有沒有時間。 [MSC, trad.]
   我想约你明天一起去吃饭，不知道你有没有时间。 [MSC, simp.]

   Wǒ xiǎng yuē nǐ míngtiān yīqǐ qù chīfàn, bù zhīdào nǐ yǒu méiyǒu shíjiān. [Pinyin]

   I'd like to invite you out to have a meal tomorrow, if you have the time.

8. ^† to hinder; to block
9. ^† to save; to economise
10. ^† frugal; economical; thrifty
11. ^† brief; concise; succinct
12. ^† poor; humble; low-ranking
13. (mathematics) to reduce (a fraction)
14. ^† to prepare; to equip
15. ^† to seek; to pursue
16. ^† to estimate; to approximate; to reckon
17. (colloquial) to weigh (on a balance or scale)
18. about; approximately

    約220大卡／约220大卡  ―  yuē 220 dàkǎ  ―  Approximately 220 kilocalories.

19. (Hong Kong, historical) district (of the City of Victoria)

    四環九約／四环九约 [Cantonese]  ―  sei³ waan⁴ gau² joek³ [Jyutping]  ―  (please add an English translation of this usage example)

20. (Hong Kong, historical) pact, group of villages (clarification of this definition is needed)

    大埔七約／大埔七约 [Cantonese]  ―  daai⁶ bou³ cat¹ joek³ [Jyutping]  ―  the seven village groups of Tai Po

約

1. ^† Alternative form of 要 (yào, “gist; essentials”)

約

1. ^† cord for the string of a stringed instrument

• “約”, in 漢語多功能字庫 (Multi-function Chinese Character Database)‎, 香港中文大學 (the Chinese University of Hong Kong), 2014–

(grade 4 “Kyōiku” kanji)

1. contract, promise
2. to contract, to shorten
3. approximately, roughly

• Go-on: やく (yaku, Jōyō); よう (yō)^{←えう (eu, historical)}
• Kan-on: やく (yaku, Jōyō); よう (yō)^{←えう (eu, historical)}
• Kun: つづまやか (tsuzumayaka, 約やか); つづめる (tsuzumeru, 約める)

• 一(いち)約(やく) (ichiyaku)
• 契(けい)約(やく) (keiyaku): contract, agreement
• 条(じょう)約(やく) (jōyaku): treaty
• 予(よ)約(やく) (yoyaku): reservation, appointment
• 約(やく)束(そく) (yakusoku): promise

• (Tokyo) や​く [yáꜜkù] (Atamadaka – [1])[1][2]
• IPA^(key): [ja̠kɯ̟ᵝ]

約(やく) • (yaku) 

1. about, approximately

   約(やく)一(いっ)ヶ月(げつ)

   yaku iggagetsu

   approximately one month

   宇宙(うちゅう)の直径(ちょっけい)は約(やく) ９３０(きゅうひゃくさんじゅう)億(おく)光年(こうねん)だ。

   Uchū no chokkei wa yaku kyūhyakusanjū-oku kōnen da.

   The diameter of the universe is some 93 billion light years.

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “Middle Korean readings, if any”)

• (SK Standard/Seoul) IPA^(key): [ja̠k̚]
• Phonetic hangul: [약]

Wikisource 約 (eumhun 맺을 약 (maejeul yak))

1. Hanja form^? of 약 (“contract, promise”).
2. Hanja form^? of 약 (“approximately, roughly”).

• 계약 (契約, gyeyak, “contract”)
• 약속 (約束, yaksok, “promise”)

約: Hán Việt readings: ước, yêu

1. chữ Hán form of ước (“contract, promise”).
2. chữ Hán form of ước (“approximately, roughly”).
3. chữ Hán form of ước (“to wish”).