Narrated Asma:

I prepared the journey food for the Prophet and Abu Bakr when they wanted (to migrate to) Medina. I said to my father (Abu Bakr), "I do not have anything to tie the container of the journey food with except my waist belt." He said, "Divide it lengthwise into two." I did so, and for this reason I was named 'Dhat-un-Nitaqain' (i.e. the owner of two belts). (Ibn 'Abbas said, "Asma', Dhat-un-Nitaq.")

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، حَدَّثَنَا هِشَامٌ، عَنْ أَبِيهِ، وَفَاطِمَةَ، عَنْ أَسْمَاءَ، رضى الله عنها صَنَعْتُ سُفْرَةً لِلنَّبِيِّ ﷺ وَأَبِي بَكْرٍ حِينَ أَرَادَا الْمَدِينَةَ، فَقُلْتُ لأَبِي مَا أَجِدُ شَيْئًا أَرْبُطُهُ إِلاَّ نِطَاقِي. قَالَ فَشُقِّيهِ. فَفَعَلْتُ، فَسُمِّيتُ ذَاتَ النِّطَاقَيْنِ.