Nirukti
The factor / thing by which people get attracted towards the dravya (substance) is known as guna (property). Definition
Unlike the residents of dravya (substance) that are responsible for kriya (activities), guna (property) is the intimate yet inactive resident of dravya and is not responsible for kriya (activities) but is responsible for attracting people towards dravya and hence is different from karma and other residents.

Number of Guna
In ayurveda guna (properties) are forty one in number and are classified as follows:

• Sartha Indriya Guna:
  Being five in number these are the guna of senses.
  
  
• Gurvadi Guna:
  Also known as "Sharirik" guna, they are twenty in number.
  
  
• Adhyatmic Guna:
  These gunas are felt only in living things and are the six gunas of Atma.
  
  
• Samanya Guna (General property):
  Total ten in number these gunas are samanya.