The noun βασιλευς (basileus; hence the English word basilica) means king, but note that until the rise of the republics (around the time of the second temple), every town of a few hundred people or more was its own kingdom.

Our word is of unclear origin but it was possibly imported from an Anatolian language — the Lydian word for king was battos. It might also have been formed from, or with the assistance of, the noun στοα (stoa), meaning pillar, perhaps because kings lived in palaces with pillars, but more so because in the era of the republic, our word βασιλευς (basileus) applied not only to whatever monarchs remained but rather to any chiefs, lords, masters and otherwise venerable persons or men of greatness or distinction: the "pillars" of society.

Here at Abarim Publications we suspect links with the Semitic words בצל (basal) and חבצלת (habasilat), which refer to flower bulbs and flower buds, the reverence of which may have helped the formation of the turban and ultimately the crown. Another word of note is the noun σεβας (sebas), reverential awe, from the verb σεβομαι (sebomai), to revere, worship or do homage to.

Note that our familiar English word "boss" has no clear etymology, other than that it probably came from the Dutch equivalent baas. The Dutch in turn, as everybody knows, have always been great at appropriating and truncating words from other languages, and may very well have drawn their noun baas from the Greek noun βασιλευς (basileus). In our day and age, we have few "kings" and many "bosses," so the latter translation is probably preferred.

In the New Testament our noun is used of David (Matthew 1:6), other Jewish kings (Luke 10:24), Herod (Matthew 2:1), Aretas, an Arabian king (2 Corinthians 11:32), and the Roman Caesar (John 19:15).

Very often this word is applied to Jesus, the king of the Jews (Matthew 2:2, Luke 19:38, John 1:49). Note that the word Christ means "anointed one" and was a synonym for the Jewish king. Christ's royalty is unique in the sense that it didn't make him the sole ruler of the world later Rome writers made him out to be, but rather because in his kingdom, everybody is sovereign and autonomous (Revelation 5:10).

This noun is used 117 times in the New Testament; see full concordance.