This hand is a stretched pair wait; I can win if a 5 or 8 comes out.
Katakana spelling is common for this mahjong term; usually written in kana.
Kanji spelling exists but is rarely used; the term is almost always written in kana.
Derived from 延べ (nobe, 'stretched') + 単 (tan, abbreviation of 単騎待ち 'single pair wait'). The exact origin within mahjong terminology is uncertain.