# \boldsymbol

Used to make a symbol or short math expression bold in math mode, especially for Greek letters or other symbols where \mathbf is not sufficient.

https://texform.dev/latex/commands/boldsymbol

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Fonts and styles](https://texform.dev/latex/topics/fonts-styles) |
| Packages | boldsymbol |
| Allowed mode | math |
| Tags | presentation |
| Commonality | medium |
| Kind | prefix |

## Syntax

### boldsymbol

Argument specification: `m`

Used to make a symbol or short math expression bold in math mode, especially for Greek letters or other symbols where \mathbf is not sufficient.

## Common tasks

### How to bold a Greek letter

\mathbf does not bold Greek; use \boldsymbol (or unicode-math \symbf).

```latex
\boldsymbol{\alpha}
```

[Open in Playground](https://play.texform.dev/?input=%5Cboldsymbol%7B%5Calpha%7D)

### How to bold an italic math symbol

```latex
\boldsymbol{x} \times \boldsymbol{y}
```

[Open in Playground](https://play.texform.dev/?input=%5Cboldsymbol%7Bx%7D+%5Ctimes+%5Cboldsymbol%7By%7D)

### How to bold a relation or operator

```latex
A \boldsymbol{\cdot} B
```

[Open in Playground](https://play.texform.dev/?input=A+%5Cboldsymbol%7B%5Ccdot%7D+B)

## Examples

```latex
\boldsymbol x
```

[Open in Playground](https://play.texform.dev/?input=%5Cboldsymbol+x)

```latex
\boldsymbol{x+y}
```

[Open in Playground](https://play.texform.dev/?input=%5Cboldsymbol%7Bx%2By%7D)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| boldsymbol | full | full | full |

## Usage frequency

2.43% of formulas in the measured corpus contain this entry, rank 23 of 263 entries with frequency data.

## In TeXForm

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

## Equivalent forms

```latex
\bm{#1}
```

exact. Requires the bm package in standard LaTeX; typically preferred over \\boldsymbol.

```latex
\mathbf{#1}
```

approximate. Applies bold Roman font, which does not bold Greek letters by default and overrides the original font family.

## Test cases

### boldsymbol

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \boldsymbol{a} | Positive: baseline | Pass | Pass | Pass |
| \boldsymbol a | Positive: bare[0] | Pass | Pass | Pass |