How to Write 闰 (rùn) — Meaning “leap (as in leap year) / extra”

Imagine a king (王) knocking on a royal door (门) to announce an extra day—"leap day." The door being slightly ajar reminds you that something extra is coming through, just like a leap year adds an extra day.

Write 门 first as two strokes: a vertical fold (丨𠃌) and then a short vertical hook (亅) inside. Inside, write 王 with three horizontal strokes and one vertical, making sure the middle horizontal of 王 aligns with the center of the door frame. A common mistake is making the inside too large or not centering it properly inside the door enclosure.

闪 means "flash" or "dodge" and has 人 (person) inside the door, while 闰 has 王 (king) inside. 闫 is a surname and has 三 (three) inside the door, not 王. Visually, 闰 has three horizontal lines inside (from 王), whereas 闪 has a person-like shape (人) and 闫 has three shorter horizontal strokes (三).

闰 appears mainly in calendar terms: 闰年 (leap year), 闰月 (leap month), and 闰日 (leap day). In traditional Chinese lunisolar calendars, a leap month is added about every three years to keep seasons aligned, which is culturally important for festivals like Chinese New Year.

Common words containing 闰 include: 闰年 (rùn nián) — leap year; 闰月 (rùn yuè) — leap month (intercalary month); 闰日 (rùn rì) — leap day.