Retjenu (rṯnw; Reṯenu, Retenu), later known as Khor, was the Ancient Egyptian name for the wider Syrian region, where the Semitic-speaking Canaanites lived. Retjenu was located between the region north of the Sinai Desert and south of the Taurus Mountains in southern Anatolia. The term Retjenu was used to refer to this geographical area since the Middle Kingdom (c. 2000–1700 BCE). The geographical areas of Retjenu were defined during the New Kingdom (c. 1550–1069 BCE) and considered to have been a collection of small states ruled by princes. The boundaries of the area considered Retjenu shifted throughout time due to military, political, and economic factors. Retjenu was divided into two geographical regions. Djahy the southernmost region covered the area between Askalon and Mount Lebanon stretching inland to the Sea of Galilee. Amurru the northern region stretched between the Lebanon and Taurus Mountains. During Thutmose III's (1479–1425 BCE) military campaigns in West Asia, the area of Djahy was referred to as Upper Retjenu and generally covered the area of Canaan. Lower Retjenu was used to refer to the area of Amurru but also incorporated the cities located along Phoenician coast.

The Egyptian term "Aamu", translated as "Asiatic", was used to refer to the people originating from the Levant. In the Twelfth Dynasty (1991–1802 BCE) text Story of Sinuhe, "Aamu" is applied about the people of Retjenu. The term "Western Asiatic" has been used to refer to the people of Retjenu but can be used to generally refer to the lands now located in modern Turkey, Iran, Iraq, Syria, Lebanon, Jordan, Palestine, Israel, the Red Sea, and the Caucasus.

The earliest documented occurrence of the term Retjenu occurs in the military campaign record of King Senusret III on the Sebek-khu Stele, detailing an Egyptian victory over the people of Retjenu: "His Majesty proceeded northward to overthrow the Asiatics. His Majesty reached a foreign country of which the name was Sekmem (...) Then Sekmem fell, together with the wretched Retjenu".

An amethyst scarab seal featuring an inscription of a personal name, title, and the term Retjenu was discovered in the site of Tell el-Dab'a dating to the Twelfth Dynasty. The scarab seal would have been received either through trade or as a diplomatic gift from the court of Egypt's Twelfth Dynasty.

In the early Twelfth Dynasty text Tale of Sinuhe (c. 1875 BC) Retjenu is a main setting and referenced in name multiple times as a defined geographical region and applied to the identity of the people residing in the area. Retjenu referenced as a defined geographical area: "When Amunenshi carried me off. He was the ruler of upper Retjenu", "This decree of the king is brought to you to inform you that your roving though countries, going from Qedem to Retjenu" and "Without calling Retjenu to mind-it is yours, even like your hounds!". The people residing in Retjenu are also referenced: "A hero of Retjenu came to provoke me in the tent; he was a peerless champion" and "When it was dawn, all Retjenu had come, having incited its tribes and gathered its neighboring countries".

The Second Stela of Kamose, the last king of the Theban 17th Dynasty (c. 1580-1550 BCE), refers to Apepi, a Hyksos Pharaoh, as a "Chieftain of Retjenu" {wr n rṯnw} implying a Canaanite background.

Within the Autobiography of Ahmose son of Abana, Retjenu is referenced in the section detailing the Syrian campaign of King Thutmose I: "After this (his majesty) proceeded to Retjenu to vent his wrath through the lands".

The Poetical Stela of Thutmose III within the Karnak Temple references Retjenu in the poem section of the stela: "I came to let you tread on those of Asia, to smite the Asians' heads in Retjenu".