Greedysort is an algorithm used to sort a list of elements in ascending order. It works by repeatedly taking the largest element from the unsorted portion of the list and placing it at the end of the sorted portion. The acronym PIG stands for 'Pick the largest item, ' HOG stands for 'Hang onto the largest item, ' and TAKER stands for 'Take the remaining elements.' Together, these three steps form the Greedysort algorithm.