janus

The god of doorways, gates and transitions, and of beginnings and endings, having two faces looking in opposite directions.

In the ages of victory, as often as the senate decreed some distant conquest, the consul denounced hostilities, by unbarring, in solemn pomp, the gates of the temple of Janus. Domestic war now rendered the admonition superfluous, and the ceremony was superseded by the establishment of a new religion. But the brazen temple of Janus was left standing in the forum; of a size sufficient only to contain the statue of the god, five cubits in height, of a human form, but with two faces, directed to the east and west.

[K]nowing that the minds of the people, rendered ferocious by a military life, would never accommodate themſelves to the practice of theſe [principles of justice, laws, and morals], during the continuance of war, he [Numa Pompilius] reſolved, by a diſuſe of arms, to mollify the fierceneſs of their temper: with this view, he built a temple to Janus, near the foot of the hill Argiletum, which was to notify a ſtate either of war or of peace: when open, it denoted that the ſtate was engaged in war; when ſhut, that there was peace with all the ſurrounding nations.

Used to indicate things with two faces (such as animals with diprosopus) or aspects; or made of two different materials; or having a two-way action.

Janus cat, Janus particle

But other categories of word-play have not been researched extensively or systematically. Among the latter is the type of word-play known as polysemous parallelism, or more commonly, Janus parallelism. The latter term was coined by Cyrus Gordon to describe a literary device in which a middle stich of poetry parallels in a polysemous manner both the line that precedes it and the line which follows it.

Used to indicate things with two faces (such as animals with diprosopus) or aspects; or made of two different materials; or having a two-way action.

Janus green B is a dye used widely in histology to stain cells for microscopic examination.

In order to show that such stains are due to oxycellulose, the fabric should be stripped with titanous chloride solution or sodium hydrosulphite. On redyeing with Janus Blue the oxycellulose patches are more heavily dyed. The writer prefers Janus Blue to the Methylene Blue which is usually recommended.

A two-faced person, a hypocrite.

The hypocrite; or, The modern Janus.

A moon of Saturn.

Heavily cratered and irregularly shaped, Janus orbits Saturn just beyond the F ring and only 50km (30 miles) farther away than its co-orbital moon, Epimetheus.

Two of Saturn's small moons have the unique distinction of sharing the same orbit. Epimetheus and Janus circle the Lord of the Rings at a distance of just over 151,000 km, about half the distance from Earth to the Moon. Both are irregularly shaped. Janus is 179 km across, while Epimetheus is about 116 km in diameter.