約 [py] yue1 [wg] yüeh [ko] 약 yak [ja] アク yaku ||| (1) An agreement, a promise, a pact, an alliance, a treaty. (2) To promise, contract, agree to, to bind. (3) To be in dire circumstances; to be in poverty. To be frugal, sparing, concise, restrained; to be cautious. (4) About, nearly, approximately. (5) About, concerning. Concerning . . .; seen from such-and-such a standpoint (āvasthika). Seen from such-and-such a perspective; seen from the standpoint of . . . (6) To shorten, contract, shrink, compress.

[Dictionary References] Naka1375b [Credit] cmuller(entry) cwittern(py)

(一)簡約、要約之意。
　(二)就、於之意。例如論廢立之時，以根機為標準而規定者，稱為「約機廢立」；由法之勝劣而規定者，則稱「約法廢立」。又如說明一事時，若自佛之一方而言，稱「約佛之所談」；若自眾生之一方而言，稱「約生之所談」。大乘義章卷十九（大四四‧八三九上）：「於此門中，四義分別：一分其相別，二約色、心、非色心等三義分別，第三約就五陰分別，第四約就六根分別。」

佛光電子大辭典

p3926

Bind, restrain; agree, covenant; about.

A Dictionary of Chinese Buddhist Terms, William Edward Soothill and Lewis Hodous

adhikṛtya, prati, -tas; yoga, samaya; adhikṛtyoktam, abhisaṃdhāya, abhisaṃdhi, ārabhya, upādāya, niyama, niyamya, bheda, mātra, vyavasthāpita, saṃdhāya

佛教漢梵大辭典

p.2789-2794