μονογενής monogenēs

Team summary, consistent with note.language.John.1.14.monogenes. The word is formed from μόνος ("only") and γένος ("kind, offspring"), not from γεννάω. Its core sense is "only member of a kind." Used of a child, it means "only (son or daughter)": Luke 7:12; 8:42; 9:38; Judg 11:34 LXX. In the LXX Psalms it renders יָחִיד (yakhid), where no birth is in view: Ps 22:20 (MT 22:21; LXX 21:21); 25:16 (LXX 24:16); 35:17 (LXX 34:17). LXX Gen 22:2, 12, 16 instead renders יָחִיד as ἀγαπητός. Isaac is μονογενής in Heb 11:17 although Abraham had other sons, so uniqueness as the son of promise is the point. Of Christ: John 1:14, 18; 3:16, 18; 1 John 4:9.

Abbott-Smith (PD) derives the word "< μόνος, γένος" and glosses it "only, only begotten." Dodson (PD) glosses it "only, only-begotten, unique." Whether a "begotten" nuance is present is debated (e.g., Irons 2017, by reference only). The team renders it "one and only (Son)" and lets context carry the filial sense.