The Surah takes its name from the word al-waqi\`ah of the very first verse.
According to the chronological order that Hadrat Abdullah bin Abbas has given of the Surahs, first Surah Ta Ha was sent down, then Al-Waqi'ah and then Ash-Shu\`ara'(Suyuti: Al-Itqan). The same sequence has been reported from Ikrimah (Baihaqi: Dala'il...
This is supported also by the story that Ibn Hisham has related from Ibn Ishaq about the affirmation of the Faith by Hadrat Umar (may Allah be pleased with him). It says that when Hadarat Umar entered his sister's house, Surah Ta Ha was being recited. Hearing his voice the people of the house hid th...