μοναὶ  [2 verses](noun pl fem nom) "Mansions" is from mone, which means (as an adjective) "alone", "solitary", "made in one piece" (as an adverb) "on one condition", "only", "all but", (as a verb) "to be alone", "to live in solitary", "to individualize" (as a noun) "abiding", "tarrying", "permanence", "stopping place", "quarters", "billets."  --  The Greek word translated as "mansions" is only translated as mansions, rooms, or apartments here in John. The closest other Greek references to this idea of rooms is from the military use as billets or quarters, that is, a longer-term stopping place where soldiers stay separately. This is opposed to staying in a military camp, where everyone stays together.

μονογενῆ [2 verses](adj sg masc acc) "Only begotten" is monogenes, which means "the only member of a kin," "only," "single," "unique," "one and the same blood," [in grammar] "having the same form in all genders," and [of plants] "growing only in one place."  -  - The term translated as "only-begotten" means "one of a kin" but more generally it means "unique" and "singular." In grammar, it also means a word having the same form in all genders, and it is kind of funny that the word, monogenes, is itself a monogenic word, having the same form in all genders. Using this word, Jesus is clearly implying that he is in some way the only son of God, the same blood and kin.

μόνῳ [4 verses](adj sg neut dat) "Alone" is from monon, which means "alone", "solitary", "only", "one above all others", "made in one piece", "single," and "unique." - The word translated as "alone" means means "alone," "solitary," "only," "single," "unique," "made in one piece".

μονόφθαλμον [2 verses](adj sg masc acc) "With one eye" is monophthalmos, which means "one-eyed." -- "One eye" is a long, complicated adjective meaning "one-eyed."

μόνοις; [18 verses](adj pl masc dat) "Only" is monos, which means "alone," "solitary," "only," "single," "unique," "made in one piece," "without [someone]," "only [something]," "unique," "one above all others," and "on one condition only." -- "Only" is an adjective that means "alone," "solitary," "only," "single," "unique," "made in one piece," "without [someone]," "only [something]," "unique," "one above all others," and "on one condition only."