O (EN)

letter, noun, particle, proper noun, symbol

letter “O”

1. uppercase form of the letter "o"
   Mellen Iech un, fir d'Iwwersetzungen vun den Beispillsätz an d'monolingual Definitioune vun all Wuert ze gesinn.

   Olivia wrote her name with a big "O" at the beginning.

noun “O”

1. a blood type that lacks A or B antigens
   Since she has type O blood, she can only receive donations from others with the same type.
2. slang for orgasm
   After months of trying, she finally experienced her first O with her partner.
3. slang for opium
   He pulled out a small pouch and whispered, "Got some O if you're looking to relax."

particle “O”

1. used for direct address
   O Captain! My Captain! Our fearful trip is done.

proper noun “O”

1. a surname from Korean or Chinese
   Mrs. O, originally from Seoul, is known for her delicious kimchi recipe.

symbol “O”

1. the symbol for oxygen
   Water is composed of two hydrogen atoms and one oxygen atom, represented chemically as H2O.
2. in mathematics, a class of functions asymptotically bounded from above by a specific function
   In algorithm analysis, if we say a sorting algorithm is O(n log n), it means its time complexity will not grow faster than n log n times some constant, for large enough n.
3. in linear algebra and group theory, symbol for orthogonal group
   In our study of symmetries, we learned that the set of rotations and reflections of a square forms an orthogonal group, denoted as O(2).