What is the meaning of Louis?

Any gold or silver coin issued by the French kings from Louis XIII to Louis XVI and bearing their image on the obverse side, particularly the gold louis d'ors, originally a French form of the Spanish doubloon but varying in value between 10 and 24 livres.

The louis d'or constitutionnel, a 24-livre gold coin issued by the First French Republic.

The franc germinal or napoleon, a similar gold coin issued by Napoleon and bearing his image on the obverse, worth 20 francs.

a louis: various gold and silver coins issued by the Kingdom, Republic, and Empire of France

20 francs

pound

Source: wiktionary.org