Originally often represented athematic vowel or a (genitive) case ending; also sometimes added simply for ease of pronunciation.Thisetymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.
In the active, attaches to the same stem as the first infinitive (by replacing the final-a or-ä). In the passive, attaches to the strong passive stem (same as the passive conditional without the final-isiin) and does not replace the final-a or-ä.
Always followed by a case marker: in standard Finnish, either the inessive or the instructive case (the latter for active only).
From theOld Norse genitive plural ending,-a, such as inmannamál (>mannemål). Also from the strong feminine genitive singular,-ar, whence also-ar- and-a-.
This interfix is often used in compounds where the first element is plural, as opposed to singular-s-. Example:gudetru(“polytheism, belief in gods”) andgudstru(“monotheism, belief in a god”).
The interfix-e- is sometimes used in compounds where the first element ends in-a:
This is especially productive when the word is the second element in a longer compound, e.g.högskola(“university”) →högskoleexamen(“university degree”);kolgruva(“coal mine”) →kolgruvearbetare(“coal mine worker”).
It is also used for some nouns ending in a consonant +/l r n/ +-a, e.g.ödla(“lizard”) →ödleart(“lizard species”);åsna(“donkey”) →åsneföl(“donkey’s foal”).
It is also used in some compounds of words ending in-a, e.g.ära(“honor”) →ärekränka(“defame”);hjärta(“heart”) →hjärtesorg(“grief, heartache”).
It is also used in some compounds ending in a consonant, e.g.natt(“night”) →nattetid(“(during) nighttime”);skörd(“harvest”) →skördetröska(“combine harvester”);tjänst(“service”) →tjänsteman(“civil servant”);tid(“time”) →tideräkning(“chronology”).
In some cases,-e- is found in more literary or archaic compounds, but not otherwise, e.g.stjärna(“star”) →stjärnevalv(“stellar vault”), cf.stjärnkikare(“astronomical telescope”)
The interfix-e- is also more common in southern and western dialects, and thus in compounds derived from those dialects, cf.-a-, e.g.spettekaka(“skewer cake”),pilevall(“avenue of willow trees”).
