Wikipedia
Al-Mu'awwidhatan ( Arabic: المعوذتان), sometimes translated as " Verses of Refuge", is an Arabic term referring to the last two suras (chapters) of the Qur'an, viz. al-Falaq (ch. 113), and An-Nās (ch. 114), which are two consecutive short prayers both beginning with the verse "Say: I seek refuge in the Lord of...". Although these two suras are separate entities in the Qur'an and also are written in the Mushaf under separate names, they are so deeply related with their contents closely resembling each other's that they have been designated by the common name 'al-Mu'awwidhatayn' (the two suras in which refuge with Allah has been sought). Imam Baihaqi in 'Dala'il an-Nubuwwah' has written that these suras were revealed together, and hence their combined name of al-Mu'awwidhatayn. There is a Sunnah tradition from Muhammad of reading them over the sick or before sleeping and they are also considered a healing.