The headword is an adjective in the feminine nominative plural; see generally LSJ s.v. tarfu/s, and Cunliffe s.v. tarfe/es. The entry is generated by its earliest attestations: Homer, Iliad 19.357 and 359 (web address 1); see further, next note. The poet describes the Achaeans as charging forth from their ships, their helmets and other battle gear as thick (and unstoppable; Edwards, pp. 276-7) as the snowflakes that come down from Zeus.
[1] The gloss is the same form as the headword, but from the adjective pukno/s, close, compact; cf. alpha 393 (gloss) and see generally LSJ s.v. The headword is identically glossed by ps.-Zonaras 1711.27; cf. Apollonius' Homeric Lexicon 149.26, the scholia to Homer, Iliad 12.158, and Hesychius. Adler also cites Lexicon Ambrosianum 77 as identical. The gloss follows the scholia to the aforementioned Homeric passages, of which the scholia vetera (as well as Etymologicum Magnum 747.20) attribute the definiens to Aristarchus (alpha 3892).