Eventual vs. Eventually ("Possibility" sense and False Friends)
The adjective eventual didn't exactly lose the "possibility" sense in English but the "finality" sense is the predominant and usual sense. Some dictionaries list the "possibility" sense as archaic but OED doesn't list it as archaic and it has an example as recent as 2013. The "possibility" sense might not be as strong as the word "possible" signifies but it is still there.
However, the adverb eventually has the strong "finally" sense and it is a good example of a false friend (faux ami) when compared to the etymologically related words in Germanic, Romance and West Slavic languages which have the "possibly" sense:
- éventuellement (French)
- eventuell (German and Swedish)
- eventualmente (Italian, Portuguese and Spanish)
- eventuelt (Norwegian)
- eventueel (Dutch)
- ewentualnie (Polish)
- eventual (Romanian)
OED's 3rd sense for eventual which suggests possibility:
That will arise or take place under certain circumstances or in a particular eventuality; contingent.
OED has an entry for an obsolete sense of eventually that might suggest possibility but it is not used today and was rarely used in the past:
In a manner dependent on events. Obsolete.
Eventual (OED's first sense):
In attributive use. Occurring or existing at the end of a process or period of time; ultimately resulting.
Eventually (OED's second sense):
In the end, finally, ultimately.
OED gives the etymology of eventual as:
< event n. + -ual suffix, perhaps after actual adj.
Compare post-classical Latin eventualis contingent, conditional (1540 or earlier).
This indicates that eventual is not directly from Latin eventualis but formed by derivation within English.
Note: The word actual is another false friend that can be analyzed further.
OED mentions the origin of event as partly a borrowing from French and partly a borrowing from Latin; and gives the etymons as French event; Latin ēventus. OED gives the etymology of event as:
< (i) Middle French event outcome, result (late 15th cent.), something that happens or takes place (16th cent.),
and its etymon (ii) classical Latin ēventus outcome, result, fulfilment, successful outcome, occurrence, fate, in post-classical Latin also chance (perhaps 4th cent.) < ēvenīre to come out, happen, result ( < ē- e- prefix2 + venīre to come: see Venite n.) + -tus, suffix forming verbal nouns.
French évent ‘one of the races or competitions which make up a programme of sport’ (1866) is a later reborrowing < English; the now usual French word for ‘event’ is événement événement n.
Word sense divergences:
The etymology of event mentions two different senses of event in Latin where the word is originated from, one of which is "chance" (emerged in post-classical Latin) so this might be a clue why there is a divergence of senses both in English and other languages. However, the "possibility" sense is older than the "finality" sense. The strong "possibility" sense in non-English languages might be retained through historical usage but the Latin eventualis, which emerged in post-classical Latin also according the OED with "possibility" sense, might have had a stronger influence on non-English languages.
Etymology of other Germanic words:
Wiktionary gives the etymology of the Germanic word eventuell as:
From Latin eventualis via French éventuel.
French Wiktionary gives the etymology of éventuel as:
(1718) Du latin eventus (« événement, ce qui advient ») avec le suffixe -el.
From Latin eventus ("event, what happens") with the suffix -el.
English loan word événement:
OED has an entry for événement which is a borrowing from French and the etymon is given as French evenement.
Now chiefly in French contexts.
An occurrence, an event; (in later use) esp. one which is particularly noteworthy or significant. Also: †an outcome, a result (obsolete).
In later use (in plural) frequently with reference to the student demonstrations, general strikes, and civil unrest which occurred in France in May 1968.
Quebec French (Québécois) word éventuellement:
Interestingly, the word éventuellement in Quebec French is used as the usual "finality" sense of English eventually unlike the Metropolitan French. It is mentioned in Wiktionary and also confirmed by the official Quebec French language site which says that this sense is a borrowing from English.
A detailed corpus research:
Additionally, I've found a corpus research in Google Books regarding eventual and its "possibility" and "finality" senses. The book is called "New frontiers of corpus research: papers from the Twenty First International Conference on English Language Research on Computerized Corpora Sydney 2000" (edited by Pam Peters, Peter Collins, Adam Smith). It also have similar deductions based on the senses listed in OED but also includes a detailed study.
Here is a relevant excerpt from the book:
An excerpt for the summary of an opinion poll from the book: