life; immortality; imperishability; continuity; friendship, wisdom and knowledge (sal sapientiae); soul.
Later also sybmolised values, sharpness and wit.
Greco-Roman: Salt has played a significant role in making sacrifices, and was apotropaic, for which it was put on the lips of Roman newborns of eight days in order to deter evil spirits, hence probably the origin of giving salt to the Christian catechumen before baptism.
Source: Ilustrovana Enciklopedija Tradicionalnih Simbola, pp152. Dz. K. Kuper, Prosveta-Nolit, Beograd, 1986 –
Original title: An Illustrated Encyclopaedia of Traditional Symbols, by Jean Campbell Cooper, Thames and Hudson, 1978, London
(this quote is a direct translation back into English form the Serbian.)