Casque vs. heaume
The French words 'casque' and 'heaume' both refer to types of helmets, but they differ in their historical context and usage.
Casque
'Casque' is a general term for helmet, used in modern French to describe various types of protective headgear.
Les motocyclistes doivent porter un casque pour leur sécurité.
(Motorcyclists must wear a helmet for their safety.)
Les pompiers portent un casque spécial pour se protéger des débris.
(Firefighters wear a special helmet to protect themselves from debris.)
Le casque de vélo est obligatoire pour les enfants.
(Bicycle helmets are mandatory for children.)
Heaume
'Heaume' specifically refers to a medieval helmet, typically worn by knights and covering the entire head.
Le chevalier portait un heaume orné de plumes.
(The knight wore a helmet adorned with feathers.)
Le heaume du roi était fait d'or et d'argent.
(The king's helmet was made of gold and silver.)
Dans les musées, on peut voir des heaumes datant du Moyen Âge.
(In museums, you can see helmets dating back to the Middle Ages.)
Summary
While 'casque' is a versatile term for modern helmets used in various contexts, 'heaume' is specifically associated with medieval armor and is rarely used in contemporary French except in historical contexts.