ポンカン

• ポンカンUsage87%
  kana-only spelling

  Standard katakana spelling; the word is usually written in kana.

• ぽんかんUsage13%

  Hiragana spelling, also common.

• ポン柑かん
  rarely-used kanji form

  Rare kanji form; the kanji 柑 means citrus.

• 椪ぽん柑かん
  ateji (phonetic kanji usage)rarely-used kanji form

  Ateji spelling; rarely used.

• 凸柑ぽんかん
  ateji (phonetic kanji usage)rarely-used kanji form

  Ateji spelling; rarely used.

The name is believed to derive from the Indian city of Pune (formerly Poona), where the fruit was first cultivated, combined with 柑 (kan, 'citrus').