In ancient Greek grammar, movable nu, movable N or ephelcystic nu (Ancient Greek: νῦ ἐφελκυστικόν nû ephelkustikón, literally "nu dragged onto" or "attracted to") is a letter nu (written ν; the Greek equivalent of the letter n) placed on the end of some grammatical forms in Attic or Ionic Greek. It is used to avoid two vowels in a row (hiatus) and to create a long syllable in poetic meter.
Movable nu may appear at the end of certain forms of verbs, nouns, and adjectives. In grammatical paradigms, it is usually written with a parenthesis to indicate that it is optional.
Movable nu is used before words starting in a vowel to prevent hiatus.
It is often omitted before consonants, but may be included there to produce a heavy syllable where the poetic meter requires one
It is often used at the end of clauses or verses.