4j

4j is a term with multiple meanings depending on context. In mathematics and electrical engineering, 4j denotes four times the imaginary unit j, where j is used in place of i to represent the square root of −1. As such, 4j is a purely imaginary number, equal to 0 + 4j in complex-number notation, and it appears in phasor diagrams, signal processing, and control theory.

4J Studios refers to a British video game developer based in Scotland. The company is best known for producing Minecraft editions for major home consoles under license from Mojang, helping bring the game to various platforms. Since its founding, 4J Studios has contributed to several console releases and updates, playing a significant role during the era when Minecraft expanded beyond PC to broader consumer devices.

In other contexts, 4j may simply be a shorthand for four times the imaginary unit in mathematical expressions, or part of a product or project name that uses j to denote the imaginary unit. As with many alphanumeric terms, its specific meaning is determined by the surrounding subject matter.