The word noodle has several meanings:

1. A long, thin strip of pasta or dough, usually made from wheat flour, rice, or other starches. Noodles come in countless varieties around the world: Italian spaghetti, Japanese ramen, Chinese lo mein, Thai pad thai. Some noodles are flat and wide, others thin as thread. You might slurp them in soup, twirl them around a fork, or stir-fry them with vegetables. Different cultures have been making noodles for thousands of years, though historians still debate whether they were invented in China or Italy first.
2. To use your head or brain, usually in the phrase use your noodle. When your mom tells you to “use your noodle,” she's asking you to think carefully and solve the problem yourself. The expression treats your brain like a tool, the same way you might use your hands or your eyes.
3. To improvise music, especially on a piano or guitar. When a musician noodles around on their instrument, they're playing casually without following sheet music, just exploring sounds and testing ideas. It's the musical equivalent of doodling in the margins of your notebook.