[1] The headword is either masculine accusative singular or neuter nominative/accusative singular of muxai/tatos, an irregular superlative of the adjective mu/xios (cf. under mu 1495). Possibly a cross-reference to kappa 2786; if not, quoted from somewhere (perhaps Josephus, who has four instances of it). LSJ entry at web address 1. [At Photius mu637 Theodoridis the editor prints this headword as muxe/staton but expresses no confidence in it.]
[2] Attested only here and, later, in Eustathius.
[3] See e.g. Aelian, De natura animalium 10.34, numbering Aphrodite as one of the Penates, whom he calls oi( qeoi\ mu/xioi. Other sources in LSJ s.v. mu/xios, II (web address 2). Aelian is available on Google Books (web address 3).