Abarim Publications' online Biblical Greek Dictionary
The noun πηγη (pege) primarily describes flowing water (or "living" water in the Hebrew vernacular), as opposed to pools of stagnant water, and hence was indicative of springs, streams, wells, fountains; all that. It appears to have started out as a generic term — Homer used this word always in plural; the streams; Hebrew too consistently speaks of מים (mayim), the waters — and later came to denote anything that flows (tears, milk, blood, light; which is actually rather striking, see our article on נהר, nahar), as well as the proverbial source or origin of anything. As the 6th century BC philosopher Heraclitus famously observed: everything flows (παντα ρει, panta rei).
The origin of our noun is a mystery, although it comes with several related terms, most notably the verb πηγαζω (pegazo), to gush forth, which clearly compares to the Hebrew verb גיח (giah), to burst forth, hence the name Gihon. From the Greek verb comes the name Pegasus, meaning gusher-forth, although this name probably commemorated the πηγη (pege), spring, where Oceanus (the primordial world-river) had been born (Pegasus' father was Poseidon).
The mystery of our word's missing pedigree is to some extend solved by its obvious proximity to the Proto-Indo-European root "pehg-", which has to do with all things hard, attached and secure — hence the Latin pax, peace, and palus, stake (a small one was called a paxilus), and thus our English words fast, fang, pact, page, propagate, peace and pole. But the mystery persists in the question why a root that means to be hard and secure yields a word that means flowing water.
The answer comes with the observation of the ancients that a living world depends not on the mere presence of water, but rather its flow: Genesis 2:6-7 declares the making of man contingent on the hydrological cycle (see for more on the hydrologic cycle our article on νεφελη, nephele, cloud), and all throughout Scriptures, rivers continue to represent entire civilizations (see our article on the name Tigris for more on this).
All this adds up to a cardinal truth of economic theory: before anything can flow, borders must be established. Before commerce can commence, property rights must be secured. Before wisdom can be exchanged, languages must be formed. Consequently, wealth comes not from the presence of value but from liquidity and liquidity from borders: not from a stash of looted gold but from trade between willing partners (see our article on Abraham), not from a head full of horded knowledge but from conversations with peers.
The related noun πηγανον (peganon) describes a kind of herb (a rue called Ruta graveolens), which was planted on the edge of gardens to serve as borders. That means that a ring of Ruta graveolens flowed around a garden like Oceanus around the κοσμος (kosmos), the world, like a winding rope that tied a bundle of branches together (the familiar fasces). The noun πηγμα (pegma) describes anything fastened; the adjective πηγος (pegos) means solid, strong or well put together (see next).
Our noun πηγη (pege), a flowing or a spring, occurs 12 times in the New Testament; see full concordance.
The verb πηγνυμι (pegnumi) means to secure or fasten and stems from the PIE root "pehg-" we discuss above. Its proximity to the noun πηγη (pege), a flowing, suggests that the securing and fastening that signifies our verb was predominantly accomplished by lengths or rope: bundled fibers that themselves are not rigorous and rather coil like rivers, but which secure and give solidity to anything they are wrapped tightly around.
In the classics our verb was used to describe the sticking in the ground of sticks, tent poles, plants or seeds (or even of a spear in someone's heart, or a kiss on someone's lips). It was also used to describe the fastening together of different parts, and hence was used to mean to build. And it was used to describe how certain solids formed from liquids: cheese from milk, ice from cooling water and crystals from warming water.
- The noun παγις (pagis), which technically describes anything that secures or fastens (a ship's anchor, for instance), but which in the classics predominantly describes a trap or snare that is designed to create bondage and the loss of freedom (this word, most famously, describes the Trojan horse). It occurs 5 times; see full concordance.
- Together with the preposition προς (pros) meaning toward: the verb προσπηγνυμι (prospegnumi), meaning to fix something to or onto something else (Acts 2:23 only).
- Together with the noun σκηνη (skene), a cover, housing or dwelling: the noun σκηνοπηγια (skenopegia), meaning dwelling- or shelter-fixing, specifically used to describe the Feast of Booths (John 7:2 only).
The noun σχοινιον (schoinion) describes a rope (John 2:15 and Acts 27:32 only). It's a diminutive of σχοινοσ (schoinos), which broadly described plants or plant-products like rush, reed or hay. These materials had many uses, among which being twisted together to form rope; hence our word. It's a synonym of δεσμος (desmo), anything that binds, from the verb δεω (deo), to bind.
It's a mystery where our word came from, and it is thought to be pre-Greek. Conveniently (or confusingly perhaps), the Hebrew verb שכן (shakan) means to dwell or to reside, but emphasizes the social identity that emerges from many people sharing a language, a culture and a body of science and technology. Noun שכן (shaken) means neighbor. The derived name Shecaniah translates as Yah Dwells or Yah Hath Taken Up His Abode, which is obviously right on par with Hebrews 8:2 (see the verb πηγνυμι, pegnumi, above).