geyya : [adj.] that which is to be sung. (nt.), a poem; a certain style of literature. || ñeyya (adj.), what should be understood.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Geyya (nt.) [grd. of gāyati, Sk. geya] a certain style of Buddhist literature consisting of mixed prose & verse. It is only found in the ster. enum of the Scriptures in their ninefold division, beginning suttaŋ geyyaŋ veyyākaraṇaŋ. See under navanga.

Pali-English Dictionary, TW Rhys Davids, William Stede,