In Egyptian mythology

Egyptian mythology

Ancient Egyptian religion was a complex system of polytheistic beliefs and rituals which were an integral part of ancient Egyptian society. It centered on the Egyptians' interaction with a multitude of deities who were believed to be present in, and in control of, the forces and elements of nature...

, Sopdet was the deification of Sothis

Sothis

Sothis is the name of a star that the Egyptians considered unusually significant. The star is not explicitly identified, but there are enough clues for modern scholars to be almost unanimous in identifying Sothis as Sirius....

, a star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 considered by almost all Egyptologists

Egyptology

Egyptology is the study of ancient Egyptian history, language, literature, religion, and art from the 5th millennium BC until the end of its native religious practices in the AD 4th century. A practitioner of the discipline is an “Egyptologist”...

 to be Sirius

Sirius

Sirius is the brightest star in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The name "Sirius" is derived from the Ancient Greek: Seirios . The star has the Bayer designation Alpha Canis Majoris...

. The name Sopdet means (she who is) sharp in Egyptian

Egyptian language

Egyptian is the oldest known indigenous language of Egypt and a branch of the Afroasiatic language family. Written records of the Egyptian language have been dated from about 3400 BC, making it one of the oldest recorded languages known. Egyptian was spoken until the late 17th century AD in the...

, a reference to the brightness of Sirius, which is the brightest star in the night sky. In art she is depicted as a woman with a five-pointed star upon her head.

Just after Sirius appears in the July sky, the Nile River begins its annual flood

Flood

A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

, and so the ancient Egyptians

Egyptians

Egyptians are nation an ethnic group made up of Mediterranean North Africans, the indigenous people of Egypt.Egyptian identity is closely tied to geography. The population of Egypt is concentrated in the lower Nile Valley, the small strip of cultivable land stretching from the First Cataract to...

 connected the two. Consequently Sopdet was identified as a goddess of the fertility of the soil, which was brought to it by the Nile's flooding. This significance led the Egyptians to base their calendar on the heliacal rising

Heliacal rising

The heliacal rising of a star occurs when it first becomes visible above the eastern horizon for a brief moment just before sunrise, after a period of time when it had not been visible....

 of Sirius.

Sopdet is the consort of Sah, the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 of Orion

Orion (constellation)

Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...

, by which Sirius appears, and the planet Venus

Venus

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

 was sometimes considered their child. The noticeably human figure of Orion was eventually identified as a form of Horus

Horus

Horus is one of the oldest and most significant deities in the Ancient Egyptian religion, who was worshipped from at least the late Predynastic period through to Greco-Roman times. Different forms of Horus are recorded in history and these are treated as distinct gods by Egyptologists...

, the sky-god, and thus, together with her being a fertility deity, this led to her being identified as a manifestation of Isis

Isis

Isis or in original more likely Aset is a goddess in Ancient Egyptian religious beliefs, whose worship spread throughout the Greco-Roman world. She was worshipped as the ideal mother and wife as well as the matron of nature and magic...

.

After Sirius' appearance, the scorching heat of summer arrives, an aspect that was referred to as Sopdu

Sopdu

In Egyptian mythology, Sopdu was originally the scorching heat of the summer sun. The effects of the scorching of the sun led many ancient cultures to see it as war-like, and the Egyptians were no different in this respect, with Sopdu consequently being seen as a war god.-In myth:Sopdu's name,...

, meaning (one who is) with Sopd, Sopd being simply the masculine form

Grammatical gender

Grammatical gender is defined linguistically as a system of classes of nouns which trigger specific types of inflections in associated words, such as adjectives, verbs and others. For a system of noun classes to be a gender system, every noun must belong to one of the classes and there should be...

, and stem

Word stem

In linguistics, a stem is a part of a word. The term is used with slightly different meanings.In one usage, a stem is a form to which affixes can be attached. Thus, in this usage, the English word friendships contains the stem friend, to which the derivational suffix -ship is attached to form a new...

, of Sopdet. Since the heat arrived after Sirius's appearance, it was said that Sopdet had given birth to it, thus Sopdu was seen as being a child of Sopdet, and thus also of Sah.