How to Write 朊 (ruǎn) — Meaning “prion”

Think of 'prion' as a tiny 'original (元) bit of meat (月)' that can cause sickness. Visualize a small, round piece of raw meat labeled "PRION" with the number 元 (first) on it to recall both the radical and the sound ruǎn.

Make sure the left part 月 is narrow and tall, with the first stroke as a left-falling slash (丿). The right part 元 starts with a horizontal stroke, then two horizontal lines below, and the final stroke is a curved hook (乚) — do not confuse it with 儿 (rén). Keep the overall width balanced, with the left side taking about one-third.

朊 (ruǎn) has 月 on the left and 元 on the right, while 有 (yǒu) has 月 with a different right side (the character 又). 朋 (péng) is two 月 side by side. Visually, 朊 has a clear horizontal line at the top of the right part, and it is much less common than both 有 and 朋.

朊 appears almost exclusively in scientific and medical contexts, specifically in the terms 朊病毒 (prion) and 朊蛋白 (prion protein). It is not an everyday character and is not part of the HSK vocabulary — you will mainly encounter it in articles about diseases like mad cow disease or Creutzfeldt-Jakob disease.

Common words containing 朊 include: 朊病毒 (ruǎn bìng dú) — prion; 朊蛋白 (ruǎn dàn bái) — prion protein; 朊 (ruǎn) — prion.