-Vn

See also: vn, VN, .vn, and Vn.

Finnish

From -hVn where the -h- has been elided between unstressed short vowels.

-an, -en, -in, -on, -un, -yn, -än, -ön (linguistic notation -Vn, V corresponds to the preceding vowel)

See the appendix on Finnish nominal cases for more information on how the illative case is used.
Used after an unstressed short vowel. The vowel is the same as the final vowel in the stem, thus producing a long vowel.

(depending on the preceding vowel (i.e. lengthens the preceding vowel)) -an, -en, -in, -on, -un, -yn, -än, -ön

From Proto-Finnic *-hën, from Proto-Uralic *-sen (third-person singular possessive suffix).

-an, -en, -än (linguistic notation -Vn, V corresponds to the preceding vowel)

Can always be replaced with -nsa, the longer third-person possessive suffix, but not the other way around. Specifically, -Vn can be used:

when the vowel preceding -nsa is a short a, ä and e (general rule, but defers to the next two)
for nominal inflections (including participles and adverbs derived from such), all cases except the nominative, genitive, illative and instructive
for verbal inflections, the long 1st infinitive, the 2nd infinitive, and the 5th infinitive

(depending on the preceding vowel (i.e. lengthens the preceding vowel)) -an, -en, -än

From the illative ending (-Vn, etymology 1) attached directly to the verb stem.

-an, -en, -in, -on, -un, -yn, -än, -ön (linguistic notation -Vn, V corresponds to the preceding vowel) (colloquial)

Example: ottaan = standard ottamaan.
Originally a Tavastian dialectal characteristic, but nowadays can be encountered in urban "non-dialectal" speech.