How to Write 膨 (péng) — Meaning “to expand; to swell”

Imagine your belly (月) swelling up like a balloon after a big meal, and the sound it makes is "péng" as it grows. The right side 彭 can be visualized as three expanding layers or ripples, reinforcing the idea of expansion.

Keep the left radical 月 narrow and straight, like a vertical slice. The right side 彭 has a top part (壴) with two horizontal lines and a vertical, followed by three slanted strokes (彡) below — make sure the three strokes are evenly spaced and not too long. A common mistake is making the entire character too wide or misplacing the three strokes.

膨 (péng) means to expand or swell, while 朦 (méng) means dim or hazy (like foggy moon), and 膀 (bǎng) means shoulder or upper arm. Visually, the right sides differ: 膨 has 彭, 朦 has 蒙, and 膀 has 旁. All share the left radical 月, but their meanings and uses are very different.

膨 appears most often in the word 膨胀 (péng zhàng), which describes physical expansion, economic inflation, or even population growth. It is also used in 膨化 (péng huà) for puffed snacks like puffed rice. While not a daily character, it is important in scientific and economic discussions.

Common words containing 膨 include: 膨胀 (péng zhàng) — to expand; to swell; inflation; 膨化 (péng huà) — puffed; expanded (usually food); 膨大 (péng dà) — to expand; to enlarge.