Upaveda means secondary knowledge. It was developed from the Vedas by the sages to elaborate Vedic teachings to be applied in various aspects of human life.
Traditionally, the four Upavedas are Ayurveda, Dhanurveda, Gandharvaveda and Arthaveda. These four present a detailed study into the various subjects important for humans to know and practice.
Ayurveda is a study of the human body and the elements affecting it. It is the ancient medical science. It states that the human body becomes ill when there is an imbalance in the three elements, which constitute the body. These elements are air or Vata, fire or Pitta and sky/earth or Kapha.
Dhanurveda means Veda of the bow but it deals with the entire study of warfare. Training, planning, line formations, weapons and their use etc. are all described in great detail in this Upaveda.
Gandharvaveda is a study of various arts like music, song, dance, etc. Its name is derived from Gandharva or an expert of music. It elaborates on the various aspects of the arts and the ways and means to excel in these arts.
Arthaveda deals with politics, administration, governance etc. It explains the meaning of a ruler, his role, laws and various other aspects dealing with this subject.
Apart from this main four, some also recognize Stahapatya and Kama Shastra as Upavedas. Stahapatya deals with architecture, buildings etc. It is mostly related to temples and its designs. Kama Shastra explores the subject of erotic love, its aspects, and explanation of physical, emotional or spiritual relationships between a man and woman and ways to improve it.