# `GSGlyph.bottomKerningGroupId`

*Instance Property*

Prefixed kerning key corresponding to [`GSGlyph.bottomKerningGroup`](/Core/GlyphsCore/GSGlyph/bottomKerningGroup).

## Declaration

```swift
var bottomKerningGroupId: String? { get set }
```

```objc
@property (nonatomic, copy) NSString * bottomKerningGroupId;
```

```python
bottomKerningGroupId() -> str
setBottomKerningGroupId_(bottomKerningGroupId: str)
```

## Discussion

Bottom-side groups use the `@MMK_T_` prefix because they occur as the first member of a vertical kerning pair.

## See Also

### Kerning Groups

- [`GSGlyph.leftKerningGroup`](/Core/GlyphsCore/GSGlyph/leftKerningGroup) — Kerning group for pairs on the left side.
- [`GSGlyph.rightKerningGroup`](/Core/GlyphsCore/GSGlyph/rightKerningGroup) — Kerning group for pairs on the right side.
- [`GSGlyph.topKerningGroup`](/Core/GlyphsCore/GSGlyph/topKerningGroup) — Kerning group for pairs on the top side.
- [`GSGlyph.bottomKerningGroup`](/Core/GlyphsCore/GSGlyph/bottomKerningGroup) — Kerning group for pairs on the bottom side.
- [`GSGlyph.leftKerningGroupId`](/Core/GlyphsCore/GSGlyph/leftKerningGroupId) — Prefixed kerning key corresponding to [`GSGlyph.leftKerningGroup`](/Core/GlyphsCore/GSGlyph/leftKerningGroup).
- [`GSGlyph.rightKerningGroupId`](/Core/GlyphsCore/GSGlyph/rightKerningGroupId) — Prefixed kerning key corresponding to [`GSGlyph.rightKerningGroup`](/Core/GlyphsCore/GSGlyph/rightKerningGroup).
- [`GSGlyph.topKerningGroupId`](/Core/GlyphsCore/GSGlyph/topKerningGroupId) — Prefixed kerning key corresponding to [`GSGlyph.topKerningGroup`](/Core/GlyphsCore/GSGlyph/topKerningGroup).
- [`GSGlyph previousKerningGroupForDirection:`](/Core/GlyphsCore/GSGlyph/previousKerningGroupForDirection:) — Kerning group on the side facing the preceding glyph for a writing direction.
- [`GSGlyph setPreviousKerningGroup:forDirection:`](/Core/GlyphsCore/GSGlyph/setPreviousKerningGroup:forDirection:) — Sets the kerning group on the side facing the preceding glyph for a writing direction.
- [`GSGlyph previousKerningGroupIDforDirection:`](/Core/GlyphsCore/GSGlyph/previousKerningGroupIDforDirection:) — Prefixed kerning key on the side facing the preceding glyph for a writing direction.
- [`GSGlyph setPreviousKerningGroupID:forDirection:`](/Core/GlyphsCore/GSGlyph/setPreviousKerningGroupID:forDirection:) — Sets the prefixed kerning key on the side facing the preceding glyph for a writing direction.
- [`GSGlyph nextKerningGroupForDirection:`](/Core/GlyphsCore/GSGlyph/nextKerningGroupForDirection:) — Kerning group on the side facing the following glyph for a writing direction.
- [`GSGlyph setNextKerningGroup:forDirection:`](/Core/GlyphsCore/GSGlyph/setNextKerningGroup:forDirection:) — Sets the kerning group on the side facing the following glyph for a writing direction.
- [`GSGlyph nextKerningGroupIDforDirection:`](/Core/GlyphsCore/GSGlyph/nextKerningGroupIDforDirection:) — Prefixed kerning key on the side facing the following glyph for a writing direction.
- [`GSGlyph setNextKerningGroupID:forDirection:`](/Core/GlyphsCore/GSGlyph/setNextKerningGroupID:forDirection:) — Sets the prefixed kerning key on the side facing the following glyph for a writing direction.