Mathematical Bold Capital Lambda

The formula defines it; bold can mark a separate variable.

In mathematical notation, boldface can mark a vector, a quantity with both size and direction, or distinguish one variable from its plain-form counterpart. The surrounding equation or its definitions tell you which role it has; capital Lambda has no single standard value.

This character encodes a mathematical bold style, but the font supplies its precise shape.

How did Lambda become a math letter?

Greek Lambda began as a letter for the /l/ sound.

Greek writers adapted the Phoenician alphabet into Greek by the early 8th century BCE, including its letter lamed 𐤋 as Lambda. It represented the Greek /l/ sound; early regional alphabets used different Lambda shapes before the familiar Λ form became standard.

The oldest surviving inscription written in Greek letters dates to about 740 BCE. Much later, mathematicians used Greek letters as formula variables, and bold style could distinguish one quantity from another.

How do I type it in LaTeX?

Write \boldsymbol{\Lambda} in LaTeX math mode.

The AMS-LaTeX command \boldsymbol typesets a bold math symbol. To store the mathematical-bold form as plain Unicode text, use 𝚲 itself.

Compatibility normalization such as NFKC can map 𝚲 to plain Λ, removing a style distinction that a formula may rely on.