Janus
/ˈd͡ʒeɪnəs/ proper noun
- proper noun (Roman mythology) The god of doorways, gates and transitions, and of beginnings and endings, having two faces looking in opposite directions.
- proper noun (attributively) 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”
- proper noun (chemistry, attributively) Used to indicate an azo dye with a quaternary ammonium group, frequently with the diazo component being safranine. “Janus green B is a dye used widely in histology to stain cells for microscopic examination.”
- proper noun (figuratively) A two-faced person, a hypocrite.
- proper noun A moon of Saturn.
- proper noun (rare) A male given name from Latin.
Etymology
From Latin Iānus (“the Roman god Janus”).
Webster’s 1913
- noun A Latin deity represented with two faces looking in opposite directions. Numa is said to have dedicated to Janus the covered passage at Rome, near the Forum, which is usually called the Temple of Janus. This passage was open in war and closed in peace. Dr. W. Smith. Janus cloth, a fabric having both sides dressed, the sides being of different colors, --used for reversible garments.
Etymology [L. See January.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “Janus”, CC BY-SA 4.0. Details