The four groups of Buddhist disciples. See 四輩.

四部弟子===（名數）與四部眾同。

丁福保《佛學大辭典》

四部弟子 (sì bù dì zǐ) 　( “the four groups of Buddhist disciples, i.e. monks, nuns, laymen, and laywomen” ) Cf. 四輩(sì bèi) etc. ;

{not found at 《漢語大詞典》3.587.} ; {not found at 《大漢和辞典》3.38.} ;

Dharmarakṣa: {66a23} 應時，其地六反震動。國中人民各取天華復散佛上。四部弟子、諸天、世人愕然疑怪(p)

{K.20.5} bhikṣu-bhikṣuṇy-upāsakôpāsikā-

Kumārajīva: {L.4a14} 比丘、比丘尼、優婆塞、優婆夷

A Digital Edition of A Glossary of Dharmarakṣa translation of the Lotus Sutra by Seishi Karashima, 1998