Definition

1. Adjective:

   • Being one more than fifty: The cardinal number fifty-one.

2. Noun:

   • Chinese distance measure: A traditional Chinese unit of distance, approximately equal to 0.5 kilometers or 500 meters.
   • A soft silver-white univalent element: The chemical element lithium (symbol Li), a soft, silvery-white alkali metal that is the lightest known metal and occurs in several minerals.

Usage Examples

• Adjective:
  • The total number of participants was li. (The total number of participants was fifty-one.)
• Noun (Distance):
  • The village is about three li from here. (The village is about three li from here.)
• Noun (Element):
  • Li is used in rechargeable batteries. (Lithium is used in rechargeable batteries.)

Advanced Usage

• As a numeral in historical/formal contexts: The adjectival form "li" (meaning fifty-one) is archaic and rarely used in modern English, having been almost entirely replaced by the Arabic numeral "51" or the word "fifty-one."
  • Chapter li of the ancient text. (Chapter fifty-one of the ancient text.)
• In technical/scientific writing: When used as a noun for the element, it is standard to capitalize the symbol "Li" but the full word "lithium" is far more common in prose.
  • The sample contained traces of Li. (The sample contained traces of lithium.)

Variants and Related Words

• Lithium (n): The full, standard English name for the chemical element Li.
  • Lithium-ion batteries are common in electronics.
• Fifty-one (adj/n): The modern English equivalent for the numeral.

Synonyms

• Adjective: Fifty-one.
• Noun (Distance): Half a kilometer (approximate).
• Noun (Element): Lithium (the standard term).

Notes on Usage

• The word "li" is a highly specialized term in English. Its use as an adjective for the number 51 is now obsolete, found primarily in historical texts or very formal numbering (like in some book chapters or legal documents).
• As a unit of measurement, "li" is used only in contexts related to Chinese culture, history, or geography. It is not a standard unit in the International System of Units.
• As the symbol for the element, "Li" is standard in chemistry, but the spoken and written form is almost always "lithium." Using "li" alone to refer to the element in general English writing would be unusual and potentially confusing.

Adjective

1. being one more than fifty

Noun

1. Chinese distance measure; approximately 0.5 kilometers
2. a soft silver-white univalent element of the alkali metal group; the lightest metal known; occurs in several minerals