A 2x12 lumber board is 1.5" thick and 11.5" wide.  2x12s come in various lengths.

2x12 boards are used for projects requiring greater strength and support, such as:

• Floor joists (providing structural support in flooring systems).
• Deck framing (like beams and joists in decks).
• General construction or large-scale woodworking projects.

2x12 boards are particularly useful when strength, stability, and a larger width are necessary. Let me know if you need more details about wood grades or specific applications!