Hydromel is a beverage.
Some people interpret the name to mean "watered down" honey, but it isn't at all, it just means that it's made with water and honey. And it while it is a type of mead, it drier than other meads.
It does not much honey flavour or aftertaste.
You start with clear or white honey and 5 times its volume of water. In North American terms, about 1 1/2 cups of honey to 8 cups of water. In metric, per 1 litre of water, 500g of honey.
The honey and water are mixed, then brought to a boil, and skimmed, then set aside to cool, yeast is added, then it is let ferment for 5 to 6 weeks. It is then siphoned to leave behind the sediment at the bottom.
It can also be flavoured with cinnamon, cardamom, ginger or other spices, lemon zest, etc. It can be distilled further to make a stronger alcohol from, or can be used to make vinegar.
People who raise bees often make it with honeycomb, to use up the honey that couldn't be extracted.
In English, Hydromel is generally assumed to be 10% alcohol or below, but Hydromels made and sold in Quebec can be as high as 15% alcohol.
Hydromel is very popular in France amongst home brewers.
Can be used in sauces.
In English, which has many terms for different kinds of mead, this French mead is seen as a "lighter mead", and so the French name is used.
Fermented Hydromel is called "hydromel vineux" in French.
A place where Hydromel is made is called a "hydromellerie" in French.