Definition

1. Noun:
   • A type of lettuce: A variety of lettuce with long, dark-green leaves that form a loosely packed, elongated head. This is often called "romaine lettuce" in American English.
   • Abbreviation for cosine: In mathematics, specifically trigonometry, it is the standard written abbreviation for the cosine function.

Usage Examples

• Noun (Lettuce):

  • I added some fresh cos to the salad for extra crunch.
  • Cos lettuce is often used in Caesar salads.

• Noun (Mathematics):

  • Calculate the value of cos 60°.
  • The formula involves finding the cos of the angle.

Advanced Usage

• "Cos" as a conjunction (Informal, chiefly British): In very informal speech and writing, especially in text messages or online chat, "cos" is a common phonetic spelling of the conjunction 'because'. This is considered non-standard.
  • I'm late cos the bus didn't come.
  • We can't go out cos it's raining.

Variants and Related Words

• Romaine (noun): The more common American English term for cos lettuce.
• Cosine (noun): The full mathematical term for the trigonometric function abbreviated as "cos".
• Because (conjunction): The standard conjunction for which "cos" is an informal abbreviation.

Synonyms

• For lettuce: Romaine, Romaine lettuce.
• For the mathematical term: Cosine (full form). There is no direct synonym for the abbreviation itself.

Notes on Different Meanings

• The two primary meanings (lettuce and mathematical abbreviation) are completely unrelated homographs (words spelled the same but with different origins and meanings).
• The informal use as "because" is a separate, colloquial development based on pronunciation.

Noun

1. lettuce with long dark-green leaves in a loosely packed elongated head
2. ratio of the adjacent side to the hypotenuse of a right-angled triangle