Tripitaka (sde snod gsum). The three collections of the teachings of Buddha Shakyamuni: Vinaya, Sutra and Abhidharma. Their purpose is the development of the three trainings of discipline, concentration and discriminating knowledge while their function is to remedy the three poisons of desire, anger and delusion.
The Tibetan version of the Tripitaka fills more than one hundred large volumes, each with more than 600 large pages. In a wider sense all of the Dharma, both Sutra and Tantra, is contained within the three collections and three trainings.
To paraphrase Khenpo Ngakchung in his Notes to the Preliminary Practices for Longchen Nyingtig: "The three collections of Hinayana scriptures, namely Vinaya, Sutra and Abhidharma, respectively express the meaning of the training in discipline, concentration and discriminating knowledge. The teachings describing the details of precepts for the bodhisattva path belong to the Vinaya collection while the meaning expressed by these scriptures are the training in discipline. The sutras expressing the gateways to samadhi are the Sutra collection while their expressed meaning, reflections on precious human body and so forth, are the training in concentration. The scriptures on the sixteen or twenty types of emptiness are the Abhidharma collection while their expressed meaning is the training in discriminating knowledge.
Scriptures expounding the details of the samayas of Vajrayana are the Vinaya collection while their expressed meaning is the training in discipline. The scriptures teaching the general points of development and completion belong to the Sutra collection, while their expressed meaning is the training in samadhi. All the scriptures expressing the Great Perfection belong to the Abhidharma collection, while their expressed meaning is the training in discriminating knowledge."