The main device (symbol) in the Lis blazon is the cross lorraine. The two main tinctures (colors) are gules and argent.
Red in heraldry is given the name Gules, sometimes said to be the “martyr’s colour”1. The colour is also associated with Mars, the red planet, and the zodiacal sign Aries 2. Later heralds of a more poetical nature would sometimes refer to the colour as ruby, after the precious stone.3.
Argent is the heraldic metal Silver and is usually shown as very pure white. It is also known more poetically as pearl, moon (or luna) 4. In a sketch or drawing it is represented by plain, unmarked paper 5.
No other symbol appearing in heraldry is subject to as much variation as the cross 6. Mediaeval Europe was a deeply religious and Christian and many of the nobility wanted to show their devotion by adopting the symbol of the cross as part of the arms. The cross lorraine is a particular variant that is especially decorative.