المعنى الاصطلاحي :

Singling Allah out in everything exclusive to Him; His Lordship, His right to be worshiped alone, and His names and attributes; and dissociating oneself from polytheism and its people.

الشرح المختصر :

"Tawheed" (monotheism) is the greatest thing that Allah, the Almighty, has made obligatory upon His slaves. It is Allah's right upon His slaves and the foundation of the mission of all the Messengers and Prophets. "Tawheed" is the belief that Allah is One and that He is unique in His creation, His dominion, and His planning. He is the only One worthy of worship, without any partners, so no acts of worship should be devoted to anyone other than Him. He has Names and Attributes that are matchless. "Tawheed" is divided into three parts: 1. "Tawheed-ul-Uluhiyyah" (maintaining the unity of Worship) 2. "Tawheed-ur-Rububiyyah" (maintaining the unity of Lordship) 3. "Tawheed-ul-Asmaa was-Sifaat" (maintaining the unity of Allah's Names and Attributes) One's belief in "tawheed" is incomplete except with an affirmation and a negation: 1. Affirming what is unique to Allah; the right to be worshiped, His Lordship, and His Names and Attributes. 2. Negating the right of Worship, Lordship as well as the divine Names and Attributes from anyone other than Allah.

التعريف اللغوي المختصر :

"Tawheed": to make something one and not numerous. Opposite: "ishraak" (polytheism) "Waahid": the first number (one). "Al-Ahad" and "Al-Waahid" refer to the unique One Who has no equivalent. Other meanings: singling out, distinguishing.