This world means the ‘observation of the birds’ and derived from the Latin worlds ‘avis’ and ‘spicio’.
The ancient Romans were observing the number of birds, their way of flying and position in the sky: A square section of the sky was divided into 4 parts and the attitudes and number of birds entering this area and moving within it gave information about the God’s will.
Of course understanding the God’s will was mainly reserved to the priests who were able to decipher the signs.
The very origin of Rome is connected to the observation of birds by Romulus and Remo.
Later on the Latin world ‘auspicium’ indicated other supernatural signs as thunders and lightning.