Appears 2 times in the Quran. (Root: دعو)
  1. And when you said to him to whom Allah had shown favor and to whom you had shown a favor: Keep your wife to yourself and be careful of (your duty to) Allah; and you concealed in your soul what Allah would bring to light, and you feared men, and Allah had a greater right that you should fear Him. But when Zaid had accomplished his want of her, We gave her to you as a wife, so that there should be no difficulty for the believers in respect of the wives of their adopted sons, when they have accomplished their want of them; and Allah's command shall be performed.

  2. And who is in greater error than he who calls besides Allah upon those that will not answer him till the day of resurrection and they are heedless of their call?