1. board; plank
それは、巨大な板だ。It is a huge board.
2. sheet (of metal); plate (of glass); pane; slab
けれど氷の板はいずれ溶ける。But the sheet of ice will eventually melt.
3. cutting board; chopping board
4. chef (esp. of high-end Japanese cuisine); cook
usu. as 板さん
5. stage (i.e. at a theatre)
役者は板の上に立つと別人になる。Actors become different people once they step onto the stage.