Greek Grammar

The mēnis wrath, mēnidos. The neanis maiden, neanidos.
Those ending in -is with a long vowel before the end are declined with -idos. The pitys pine tree, pityos. The chlamys cloak, chlamydos.
Those ending in -ys that are barytone not having an acute accent on the last syllable are declined with -yos. Those that are oxytone acute-accented on the final syllable are declined with -ydos, except for ilys mud, ilyos.

Concerning neuter nouns.

The bēma step/platform, bēmatos. The dōma house/roof, dōmatos. The schēma form/shape, schēmatos. The doma gift, domatos. Neuter nouns ending in -a have a mute mu before the end and are declined with -tos. The meli honey, melitos.
Neuter nouns ending in -i that are single-gender or common are declined with -tos. The pōy flock, pōos.
The gony knee, gonyos. The dory spear, doryos.
For those ending in -y: those that have a long vowel before the end are declined with -eos, and those that have a short vowel are declined with -yos. Gony, gonyos. Dory, doryos, and gounos of a knee and douros of a spear are said by metathesis transposition of sounds. The delear bait, deleatos. The ear spring, earos. The helōr prey, helōros. The hēpar liver, hēpatos. Neuter nouns ending in -r form the genitive in -ros, except for some heteroclite irregularly declined ones: phrear well.