Abarim Publications' online Biblical Greek Dictionary
The noun χοιρος (choiros) means pig or piglet, but comes with quite a footnote. Like our English words pig, swine, hog and boar (the latter two technically denote the male pig), the Greek words for pig are used with considerable overlap. A mature male pig was referred to either by our word χοιρος (choiros), or by the noun υς (hus), which was also the word for wild swine (see below).
A mature female pig, however, was referred to by the noun δελφαξ (delphax), from the same root as δελφυς (delphus), meaning womb, from the Proto-Indo-European root "gwelbh-", meaning womb — hence also the word αδελφος (adelphos), meaning brother or womb-mate, our English word dolphin, the pig-of-the-sea, and the ethnonym Δελφος (Delphos), a Delphian, someone from Delphi (Δελφι, Delphi). The word for adult sow coming from the word for womb is rather striking, also because our noun χοιρος (choiros) was used derogatorily to refer to a young woman's pudenda (probably after the lack of pubic hair; see Song of Solomon 8:8 for a comparable observation).
Somehow the ancients sensed a deep kinship between humans and pigs (and dolphins). Both have largely hairless skin and subcutaneous fat, and their eyes are remarkably similar in iris-pigmentation and eyelashes. More convincing, perhaps, is the unexpected degree of similarity between pig DNA and ape DNA, which suggests that unlike earlier classifications, the pig line ought to be regarded as an early offshoot from the simian line; a lost brother rather than a very distant cousin. Perhaps this explains why the Jews were strictly forbidden to eat pig. And it may also help to explain how Circe could transform Odysseus' men into pigs, not by utterly changing their genetic constitution, but by activating long forgotten but still very present traits (in Spirited Away, 2001, Chihiro's parents also change into pigs, following a similar cultural tradition). A very similar story is told in the gospels, as the demonic infestation of the man named Legion (or two unnamed men in Matthew's version) seamlessly transferred to the swine (Matthew 8:28-34, Mark 5:1-20, Luke 8:26-39).
Our word χοιρος (choiros) ultimately stems from the Proto-Indo-European root "gher-", meaning to be hairy or bristly (hence too our English word hair), which is rather curious because domesticated pigs are notoriously hairless. But significantly, our English word horror comes from the same PIE root. And the link between hairy and horror is not an accidental one, since it also exists in the Hebrew root שער (sa'ar). The adjective שעיר (sa'ir) means hairy and noun שער (se'ar) means hair or hairdo. But the denominative verb שער (sa'ar) means to be very afraid, noun שער (sa'r), means horror, adjective שער (sho'ar), horrid, and nouns שערורה (sha'arura), שערוריה (sha'aruriya) and שעררית (sha'arurit) denote horror or horrible things.
A head of long, flowing hair marks an adult mind (hence the long hair of the Nazirite), but both our roots "gher-" and שער (sa'ar) refer to the bristly tufts that mark immaturity. A young woman's pudenda was called piglet because of its immature pubic hair, and pigs were likewise known for their signature immaturity of mind, which made them not only largely bald but also prone to panic and stampede at the first little signs of anything unfamiliar. To the ancients, pigs were proverbial pussies.
From the same Hebrew root, the noun שערה (se'ora) means barley, the bearded grain that served as animal fodder and the basis of beer. Barley was also the proverbial counterpart of wheat, from which bread was commonly made (see σιτος, sitos, grain). The word for goat also derives from this same root, namely שעיר (sa'ir), and so does the identical name Seir, belonging to the mountain of Esau. All this suggests that the familiar poetic arc that gave us the broken symmetry of the constellation Gemini, also exists between goats and sheep (Matthew 25:32), Seir and Israel (Romans 9:13), beer and wine, and ultimately pigs and humans (or sheep).
The command to not-fear is the most repeated command in the Bible, and also the first command that Logos impressed upon Abraham (Genesis 15:1). Fear is of course a perfectly sound emotion that warns for unfamiliar and thus potentially dangerous sights, but mankind began to separate from its own nature by investing in stronger social networks, and thus a more intelligent society, based on words and law (see ελευθερια, eleutheria, freedom-by-law), which allowed man to turn swords into plows and fear into laughter (which explains why fear and laughter are accompanied by identical physical processes). Hence, Abraham's son was named Isaac, which means He Will Cause To Laugh. Isaac's sons were Esau and Jacob, the former was hairy and inhabited Seir, the latter was smooth and became Israel.
Since Adam represents every living being (as Eve is the "mother of all living" or the biosphere), the circle of salvation (that is the family from which the Christ was to come), grew narrower in Noah (all homo sapiens), narrower still in Abraham (all international trade), and narrower still in Isaac, then Jacob and finally Judah. It appears that in antiquity, pigs were known as the Hairy or Fearful Bunch, which were in relatively recent history a member of the circle of salvation, but dropped out on account of their cowardice and tendency to either do nothing or else stampede and destroy everything (Matthew 7:6). The circle of salvation went on as the Naked or Fearless Ape (who was actually a weaker individual but fearless because of the complexity of his social network and subsequent language skills).
The difference between a shepherd and a pig herder is that a shepherd walks ahead of the sheep and the sheep follow him because they know and trust him, whereas a pig herder walks behind the pigs and drives them violently to where they don't want to go. Sheep know their shepherd and know that he leads them to grassy pastures and fresh streams, whilst keeping them safe, and so stay willingly in his vicinity. Pigs, on the other hand, don't acknowledge authority, have no clue what's good for them and try to escape into the wilderness (where their bouncy pink hams get hunted and eaten by wolves).
Although our noun χοιρος (choiros) most literally means bristly or horrified one, in Greek it fits right into the cluster of words that also contained the noun χωρος (choros), bordered off plot of agricultural land, the adverb χωρις (choris), meaning separately, the noun χορτος (chortos), pasture or garden, and even the verb χαιρω (chairo), to be socially joyful, and the noun χορος (choros), choir. That suggests that to the Greeks (and Romans), pigs were known as Choir Boys and Party People. This may also help to explain why they bred them specifically to be sacrificed to their gods.
Our noun χοιρος (choiros), pig or piglet, is used 14 times; see full concordance.