What does 'laminoe' as used by Gene Wolfe in Peace mean?
It is a typo or an OCR error for lamiae, the Latin plural of lamia. My hardcopy (the 2012 edition from Orb) has lamiae.
From Wiktionary:
lamia f (genitive lamiae); first declension
- witch who was said to suck children's blood (sort of female bogeyman)
- a sorceress, enchantress, witch.
Lamia was originally a Greek word, but there is no Greek plural, since there was only one Lamia in Greek myth (and the Greek plural wouldn't have been laminoe, either).