The shortest useful answer is geographical: Ireland and the United States commonly use whiskey, while Scotland, Canada and Japan commonly use whisky. But labels do not always follow the pattern, and neither spelling defines how the liquid was made.
Where the split came from
The English word developed from Gaelic expressions often translated as “water of life.” As Irish and Scottish distilling traditions became commercial industries, different English spellings settled into use. Irish producers widely adopted “whiskey”; Scotch producers standardized around “whisky.” American distillers inherited influences from several immigrant traditions, so most—but not all—use the Irish spelling.
What spelling cannot tell you
An “e” does not reveal the grain recipe, still type, number of distillations, cask, age or flavour. Those details come from the category and label. Bourbon whiskey must satisfy American production rules; single malt Scotch whisky satisfies a different set of Scottish rules. Both belong to whiskey’s wider family.
Why this site is Whiskey.lt
We use whiskey as the broad editorial term because it is widely understood in international English and matches our domain. When discussing a protected category or a producer, we follow its own spelling.
The point to remember
Treat the spelling as a signpost to tradition, not a test of authenticity. If you want to know what is in the glass, the next questions are where it was made, which grains were used, how it was distilled and how it matured.