Belgicism
"Belgicism" is the English word for "Belgicisme" (a French word). It's the little differences between the French which is spoken in France and the one which is spoken in Belgium.
Teachers don't usually teach "Belgicism" because the teach French from France.
Teachers don't usually teach "Belgicism" because the teach French from France.
In Belgium, people might say : "J'ai trouvé ce magnifique pyjama ligné" which means "I've found this wonderful striped pyjama" but in France, people would say : "J'ai trouvé ce magnifique pyjama rayé". So "Ligné" which means "Striped" is a Belgicism.