五一

wǔyī
5-1 (May 1st)

CEDICT

short for 五一國際勞動節／五一国际劳动节 (wǔyī guójì láodòngjié, “May Day”)

Wiktionary

五一國際勞動節／五一国际劳动节的簡稱。

維基詞典

Entry Composition

1 五 wǔ
  1. five
  2. 5
2 一 yī
  1. one
  2. single
  3. a (article)
  4. as soon as
  5. entire; whole; all; throughout
  6. "one" radical in Chinese characters (Kangxi radical 1)
  7. also pr. yāo for greater clarity when spelling out numbers digit by digit

Containing this entry

一五一十 yīwǔyīshí lit. count by fives and tens (idiom); to narrate systematically and in full detail
五一國際勞動節 wǔyīguójìláodòngjié