Nidana = A rope for tying up a calf]. The first or essential cause. Diagnosis of a disease. According to Buddhism, the 12 causes of finite existence, each one arising out of the other progressively are Avidya (ignorance), Samskara (proclivities), Vijnana (consciousness), Namarupa (name and form), Chadyatana (the senses and their objects), Sparsha (contact), Vedana (feeling), Trishna (thirst), Upadana (clinging), Bhava (becoming), Jati (caste, birth-categorisation), and Jaramaranam (old age and death).
The term nidana is a Sanskrit word (from ni = down, into + the verbal root da = to bind). It means 'chain of causation,' and is attributed to Shakyamuni Buddha. It has two specific meanings within Buddhism.