Abarim Publications' online Biblical Greek Dictionary
γωνια
The noun γωνια (gonia) means angle or corner, and stems from the same Proto-Indo-European root "gonu-", knee or bend, as the English noun knee and the Greek noun γονυ (gonu), also meaning knee, see below. The Hebrew equivalent of our noun, namely פנה (pinna), comes from the verb פנה (pana), to turn, from which also comes the plural noun פנים (panim), meaning features or face, and names like Peniel and Penuel.
Our noun γωνια (gonia) is used 9 times in the New Testament, see full concordance, and from it derive:
- Together with the noun ακρον (akron) meaning extremity: the noun ακρογωνιαιος (akrogoniaios), meaning corner-stone, main aspect, most prominent feature, foundation or pyramidal apex (Ephesians 2:20 and 1 Peter 2:6 only). This word is not a common Greek or even Roman term but instead translates the Hebrew term אבן ראש פנה ('eben rosh paneh): stone of chief turning.
- Together with the numeral τετρα (tetra), meaning four: the adjective τετραγωνος (tetragonos), which means four-cornered in the same way in which a pentagon is five-cornered (Revelation 21:16 only; the Septuagint uses this same word in Exodus 27:1 and Ezekiel 41:21).
γονυ
The noun γονυ (gonu) means knee and stems from the same Proto-Indo-European root "gonu-", knee or bend, as the noun γωνια (gonia), angle or corner, discussed above. In the New Testament, our noun is often coupled with the verb καμπτω (kampto), to bend, or τιθημι (tithemi), to set, in order to describe a posture in which one prayed (on bended knees).
The Hebrew word for knee is ברך (berek), which derives from the verb ברך (barak), which originally meant to kneel, but which came to mean to bless, probably since a person who was to receive a blessing commonly took a knee. From this latter verb comes the name Baruch or Blessed One. Without bendable knees, a person could neither kneel nor walk.
Our noun γονυ (gonu), knee, is used 12 times, see full concordance, and from it comes:
- Together with the verb πιπτω (pipto), to fall or lower: the verb γονυπετεω (gonupeteo), meaning to get down on one's knees; to kneel. This verb is used 4 times; see full concordance.