It means causative factor. The broad meaning of Nidana includes diagnosis and knowledge of disease. The section Nidana Sthana deals with knowledge of disease in detail.
- Hetu - purpose ,reason, intention
- nimitta-shakuna(omen or prognostic), instrumental or efficient cause, target, indication
- ayatana-means the site which provide shelter.
- karta -perpetrator; that which act as cause of disease
- karana-fundamental cause
- pratyaya-cause used in terms of faith also
- samutthana- the origin of disease
Nidana is of three types:
- Asatmyendriyarthasamyoga (unsuitable contact of sense organs with their objects)
- Pragyaparadha (intellectual errors or knowingly engaging in harmful activities), and
- Kala (time, seasonal, temporal factors).