noun, noun which may take the genitive case particle 'no'
three dimensions; 3D; three-dimensional
Standard term for three-dimensional space or objects; used in mathematics, physics, computer graphics, and everyday contexts.
この映画は三次元で見ると迫力が違う。
This movie is much more impressive when watched in 3D.
三次元の座標
Calculate the three-dimensional coordinates.
noun, noun which may take the genitive case particle 'no'
real world; IRL; in real life
Slang used in otaku and internet culture to refer to the real world, as opposed to the two-dimensional world of anime and manga. Often humorous or self-deprecating.
三次元の彼女が欲しいけど、なかなかできない。
I want a real-life girlfriend, but it's not easy.
オタクにとって三次元は厳しい場所だ。
For otaku, the real world is a harsh place.