The basic format of a CEDICT entry is:

Traditional Simplified [pin1 yin1] /English equivalent 1/equivalent 2/

For example:

中國 中国 [Zhong1 guo2] /China/Middle Kingdom/

Additionally:

• The Chinese word should consist of one or more Chinese characters, without any spaces in it
• The Mandarin pinyin should follow in the format below:
  • It should have a space between each pinyin syllable
  • Each pinyin syllable should have a tone number. Use 5 for the light tone (e.g. ni3 hao3 ma5)
  • Raw tones should be used:
    • Tone sandhi is not indicated (e.g., ni3 hao3 is not changed to ni2 hao3)
    • Although “yi” and “bu” have various modifications in tone, depending on what follows them, these are not indicated in writing (e.g., “one horse” is pronounced “yi4 pi3 ma3” but written “yi1 pi3 ma3”, and “not enough” is pronounced “bu2 gou4” but written “bu4 gou4”)
    • Word-related changes to neutral tone, however, are indicated. These are especially common with reduplicated forms (e.g., use ma1 ma5, not ma1 ma1; ba4 ba5, not ba4 ba4; kan4 kan5, not kan4 kan4; xiang3 xiang5 (“take under consideration”), not xiang3 xiang3). This isn't limited to reduplicated forms, e.g., ming2 bai5, not ming2 bai2; cong1 ming5, not cong1 ming2.
      It's best to keep in mind that Pinyin is about Mandarin words, not Chinese characters.
  • For pinyin that uses the ü, represent it with a u followed by a colon (e.g. nu:3 ren2)
  • Capitalize pinyin for proper nouns (e.g. Bei3 jing1)
• The English definitions should be separated with the '/' character (e.g. /English equivalent 1/equivalent 2/).
• American English should be used for the English definitions
• Do not add definite or indefinite articles (e.g. “a”, “an”, “the”, etc) to English nouns unless they are necessary to distinguish the word from another usage type or homonym