There are several types of whiskey common to Ireland. Single Malt (A whiskey made from 100% malted barley); Pure Pot Still (A whiskey made from a mixture of malted & unmalted barley), and Blended Whiskey (A whiskey made from a blend of malted barley and non-malted grains such as corn or wheat).
Note the difference in how the Irish spell "whiskey" (with an "e") and how the Scottish spell it"whisky". There is no known reason, legal or otherwise why this difference exists.
Peat is almost never used in the malting process, resulting in a whiskey with an arguably smoother, sweeter flavour. In most Irish whiskey, the smoky, earthy overtones of Scotch are absent. A notable exception to this is Connemara Peated Malt whiskey.
The word whiskey is an Anglicization of the Irish language term "uisce beatha" which translates as "water of life". Craythur is an Irish term for whiskey.