Cetus
Cetus is a Zodiacal constellation otherwise known as the Sea Monster. It is one of the 48 Greek constellations originally described by the 2nd century astronomer Claudius Ptolemy (Wikipedia). Cetus remains one of the 88 modern constellations defined by the International Astronomical Union (Wikipedia).
Cetus (abbrev. = Cet; genitive = Ceti) covers 1231 square degrees or 2.99% of the celestial sphere making it the 4th largest constellation. It contains 189 stars brighter than apparent magnitude 6.5, the brightest star being Diphda.
For more information see the entries for Cetus at Wikipedia and U. Wisconsin. For a chart of Cetus, see Cet (IAU).