Triangle Symbols

Triangles are among the most versatile geometric symbols in Unicode. They serve as directional indicators in user interfaces, operators in mathematics, decorative elements in typography, and building blocks in technical diagrams. Unicode encodes dozens of triangle variants across several blocks, covering every combination of direction (up, down, left, right), style (filled, outlined, small, medium), and purpose (geometric, pointing, mathematical). This guide catalogs every Unicode triangle character, explains where each one lives in the standard, and provides copy-paste references for developers and designers.

Quick Copy-Paste Table

Geometric Shapes Block (U+25A0–U+25FF)

The Geometric Shapes block is the primary home for triangle symbols in Unicode. It contains a systematic family of triangles organized by direction and style.

Up-Pointing Triangles

The upward triangle is the most commonly used direction. ▲ (U+25B2) is the filled "black" variant, while △ (U+25B3) is the outlined "white" variant. The naming convention in Unicode uses "black" to mean filled and "white" to mean outlined, regardless of the actual rendering color (which depends on the font and CSS styling).

The small variants ▴ (U+25B4) and ▵ (U+25B5) are designed for inline text use. They render at roughly half the height of their full-sized counterparts and are ideal for compact table headers or list markers.

<span>▲ Sort ascending</span>
<span>△ Priority: normal</span>
<span>Price ▴ (sorted)</span>

Down-Pointing Triangles

▼ (U+25BC) and ▽ (U+25BD) mirror the up-pointing set. ▼ is ubiquitous in UI design as the disclosure triangle for dropdown menus and collapsible sections.

<button>Select option ▼</button>
<details>
  <summary>More info ▾</summary>
  <p>Hidden content here.</p>
</details>

Left and Right Triangles

◀ (U+25C0) and ▶ (U+25B6) are commonly used as media playback controls. ▶ in particular is the universally recognized "play" icon. Note that ▶ (U+25B6) and ◀ (U+25C0) may render as emoji on some platforms — if you need guaranteed text rendering, use the variation selector U+FE0E:

<span>&#x25B6;&#xFE0E; Play</span>
<span>&#x25C0;&#xFE0E; Previous</span>

Corner Triangles

The corner triangles ◢ (U+25E2), ◣ (U+25E3), ◤ (U+25E4), and ◥ (U+25E5) are right triangles with their hypotenuse on one side. These are used for decorative borders, corner decorations, and graphical layouts in text-based interfaces.

Mathematical Triangles

Unicode also encodes triangles used specifically in mathematical notation, primarily in the Mathematical Operators block (U+2200–U+22FF) and Miscellaneous Mathematical Symbols-B (U+2980–U+29FF):

Delta vs Triangle

A common point of confusion: ∆ (U+2206, INCREMENT) and △ (U+25B3, WHITE UP-POINTING TRIANGLE) look nearly identical in many fonts but are semantically different characters. ∆ belongs to the Mathematical Operators block and is intended for mathematical contexts like "Δx" (change in x). △ belongs to Geometric Shapes and is intended for graphical/decorative use.

Similarly, ∇ (U+2207, NABLA) is the mathematical operator for the gradient/del vector operator, while ▽ (U+25BD) is the geometric shape. In practice, many authors interchange these — but for semantic correctness in scientific documents, use the mathematical operators.

Triangles in UI Design

Triangles are essential UI primitives. Here are common patterns:

Disclosure Triangles

/* CSS-only disclosure triangle using Unicode */
.disclosure::before {
    content: "▸";  /* U+25B8 collapsed */
}
.disclosure.open::before {
    content: "▾";  /* U+25BE expanded */
}

Sort Indicators

Table headers commonly use small triangles to indicate sort direction:

<th>Name ▴</th>   <!-- sorted ascending -->
<th>Date ▾</th>   <!-- sorted descending -->
<th>Size</th>      <!-- unsorted -->

Breadcrumb Separators

<nav>Home ▸ Products ▸ Electronics ▸ Headphones</nav>

Keyboard Shortcuts and Input Methods

Font Support and Rendering

Triangle characters enjoy excellent font support. All major system fonts (Arial, Helvetica, Times New Roman, Segoe UI, San Francisco, Noto Sans) include the core Geometric Shapes block. However, rendering varies:

• Filled triangles (▲▼◀▶) are the most consistent across platforms.
• Outline triangles (△▽◁▷) may appear with varying stroke widths.
• Small triangles (▴▵▸▹▾▿◂◃) may be indistinguishable from their full-size counterparts in some fonts.
• ▶ and ◀ may render as emoji by default on iOS/Android. Append U+FE0E (Variation Selector-15) to force text presentation.

Key Takeaways

• Unicode encodes 20+ triangle characters in the Geometric Shapes block (U+25A0–U+25FF), systematically organized by direction (up, down, left, right), fill (black/white), and size (normal/small).
• Mathematical triangles ∆ (U+2206) and ∇ (U+2207) are semantically distinct from geometric triangles △ (U+25B3) and ▽ (U+25BD) — use the correct character for context.
• ▶ (U+25B6) may render as emoji on mobile platforms; append U+FE0E for guaranteed text rendering.
• Corner triangles ◢◣◤◥ are right triangles useful for decorative borders in text art.
• For UI development, the small triangle variants (▴▾▸◂) are ideal for inline indicators like sort arrows, breadcrumbs, and disclosure controls.