The headword is a feminine noun in the nominative (and vocative) singular; see again phi 225, and generally LSJ s.v., citing early instances in Herodotus, Euripides and Xenophon. For its occurrence in the accusative case in Polybius 18.35.6 (web address 1) cf. lambda 330, and n. 1 below.
A development from this word is the neuter plural para/ferna, defined in LSJ s.v. as 'goods which a bride brings over and above her dowry'; and that in turn generates the original and technical sense of the English paraphernalia.
[1] The headword is glossed thus by Aristophanes of Byzantium, and thereafter in (e.g.) Hesychius, Photius phi120 Theodoridis, and ps.-Zonaras 1802.10. The Suda inserts the gloss into the aforementioned Polybius extract at lambda 330. [In her critical apparatus Adler notes that ms V transmits h( proi=c, with circumflex accent instead of acute.]
[2] Note the accentuation of the headword on the penult here, though Theodoridis rejects it (for fernh/) for Photius phi119. [Adler reports that in mss FV this is a new entry, whereas ms G omits the addendum.]