The four groups of Buddhist disciples. See 四輩.

四部之會 (sì bù zhī huì) 　( “the fourfold assemblies 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: {124c17} 持是經者 淨徳常然 則爲見佛 大聖導師 及吾於世 滅度大通 則此一切 諸菩薩衆 并復覩此 四部之會(v)

{K.393.4} parṣāś ……catvāri

Kumārajīva: {not found at L.52b14} 

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