Rum is a liquor made by fermenting and then distilling sugarcane molasses or sugarcane juice. The sugarcane is fermented with water and yeast to produce a beer-like liquid called "wash". The wash is then distilled to produce a clear liquid called the distillate. The distillate is often aged in barrels of oak to give it its characteristic color and flavor.

Most rum is produced from molasses, which is made from sugarcane. However, rum can also be made by distilling the beery type liquid produced from fermented fresh sugarcane juice, which is known as "rhum agricole". This method of rum production is common on the French islands, particularly Martinique. Rum can also be made from cane syrup, which is made by boiling cane juice to remove some of its water content.

The quality of rum depends on the quality and variety of the sugarcane that was used to create it. The climate and soil type where the sugarcane was grown also impact the final taste of the rum.

In summary, rum is made from sugarcane molasses or sugarcane juice that is fermented and then distilled. The resulting clear liquid is often aged in oak barrels to give it its characteristic color and flavor.