What is the difference between Tantra and Buddhism

There have been many schools of Chinese Buddhism, mainly eight. One is the Sanlun Sect a.k.a. Dharma Nature Sect, the second is the Yoga Sect a.k.a. Dharma Sang Sect, the third is the Tiantai Sect, the fourth is the Hsien Shou Sect a.k.a. Huayan Sect, the fifth is the Ch'an Sect, the sixth is the Pure Land Sect, the seventh is the Ritsu Sect, and the eighth is the Tantric Sect a.k.a. the Truth Sect. These are the eight sects commonly referred to as Sex, Sang, T'ai, Hsien, Ch'an, Pure Land, Ritual, and Tantra.