Although historic and historical have some overlap in meaning, they are usefully differentiated.
Historical, the more general and common word, means of history, of the nature of history, relating to history, belonging to history, occurring in history, and so on. The Oxford English Dictionary was originally called A New English Dictionary on Historical Principles. We read historical fiction and perform historical research (which, if we are lucky, might become historic).
Historic is used less often, and generally means historically famous, historically important, etc.: the president’s historic speech; preserving historic buildings; a historic moment for the country. Historic can refer to present events if they are obviously momentous enough.
William Safire summarised the distinction thus: “Any past event is historical, but only the most memorable ones are historic.” Yet the distinction is not absolute. In one sense historic is a subset of historical, so blurring inevitably occurs. Historic sometimes carries the broad meaning associated more strongly with historical, while historical can refer to something (or someone*) historically significant, i.e. historic. These crossover usages are not wrong, but by avoiding them you will help maintain a convenient semantic division.
Once again I find myself agreeing with Merriam-Webster, who after reviewing the historical evidence conclude that “bucking [the trend] may be historically justified but is more likely to interfere with the smooth transfer of your ideas from paper to reader.” This is because some readers – including many English language authorities – insist on keeping the words’ meanings separate. In The Complete Plain Words, for example, Ernest Gowers stresses that their “useful differentiation should not be blurred by the use of one for the other”.
A note on pronunciation: In both words /(h)ɪ’stɒrɪk/ and /(h)ɪ’stɒrɪk(ə)l/ the h can be aspirated or not; if it is not, an is the accompanying indefinite article. When the stress falls on the second syllable, the h is weakened, hence some people’s preference for an: compare a(n) historian with a history. Be aware, though, that this preference seems quaint to some, and that a historic is the dominant modern form.
* According to Loose Talk: The GUBU File by Damian Corless, a presenter of Eurovision said to Ireland’s winner, “Johnny Logan, you are historical!” Unfortunately, I can neither remember this nor find video evidence for it.
Sentence first 
Maybe Corless meant “hysterical” rather than “historical”… (And I’ll be deep in the cold, cold ground before I say “a historic”! But then again, I tend to use “an” before h-words more than is strictly necessary (or correct)).
Doubtful: Funnily enough, Corless attributes the Eurovision quote to “Hysterical Swiss presenter of Eurovision“. As to a or an, I don’t think my spoken usage is fully consistent, but I don’t think that’s necessarily a bad thing. Certainly there are differences between spoken and written usage, and in both there is variation according to context.
Hmmm. Methinks the use of ‘historic’ on any occasion, in any sentence, irrespective of context, is a nightmare from which the English-speaking world would do well to awake.
A harsh assessment, PK. Why the zero tolerance?
I don’t know. Peccadillo of mine, I guess… just like my fondness for dressing up in pigsflesh and doing the hokey-cokey. I just find the word superfluous in the extreme. Everything that is is historic. Even the prehistoric is historic.
P.S. Just kidding about the hokey-cokey
I see what you mean. I did wonder whether you had taken a contrary philosophical stance about it. (I also wondered whether it was the word’s occasional abuse and overuse that bothered you.) We all have pet lexical peeves, I suppose. But faulting language for being illogical, especially when it has to do with time, is asking for trouble. Not that I don’t do it myself now and then.
Yes, you’re right, Stan, and I appreciate that if language has any redeeming virtue then it must certainly lie in its schizoid adaptivity and hence its inevitable lurch toward absolute senselessness. At which future point I will gloatfully cry: ‘Ha! Eat that, language.’
PK: While you’re gloating you may as well go the whole hog (there’s the pigsflesh again). I think language has many redeeming virtues, but it also profoundly complicates how we perceive and interpret the world, often in unnoticed ways. You know I know you already know this, but language has been eating itself ever since it became flesh. It’s a recursive semantic knot.
Hm, I do agree with PK.
The German language – as far as I know – does not make a difference; everything is historisch, i.e historic/historical.
And, in whatever village a (new) sewage plant is to ‘inaugurate’, next day – or ten days later hahaha -in the local newspaper the mayor will be qoted saying: “This is a historic day for our village.”
Ahem, and I am not talking about the Obamas, Merkels, Sarkozys and Cowans, so far …
… rather I shall retreat under the rocks of Seanhenge and make my maths … or was it arithmetics?
Ha ha … All this, just to say: Another good and thought-provoking post, Stan. Thanks.
Sean: Perhaps ‘folgenschwer’ carries a similar meaning to ‘historic’?
Although it is in the nature of (some) news media to sensationalise whenever possible – at least in accordance with their readers’ expectations – round here a new sewage plant is more likely to be notorious than historic!
[…] that the barrister intended the idiom make history (or possibly break with history*). Given the historic nature of the trial, he may have blended making history with breaking news. Or maybe he meant […]