The Akhand Path (Punjabi: ਅਖੰਡ ਪਾਠ) is the continuous and uninterrupted recitation of the Guru Granth Sahib, the principal scripture revered in the Sikh tradition. The practice is also referred to as Akhand Path Sahib.
As the term suggests, the recitation proceeds without pause from the beginning of the scripture to its conclusion. The Guru Granth Sahib, treated as the eternal Guru in Sikh belief, is read aloud in its entirety as part of this observance.
Adapted from the English Wikipedia article on Akhand Path.