1. Completely absorbed or preoccupied: This is the most common meaning. It describes someone who is deeply focused on something, to the point of being unaware of their surroundings.
* Example: "He was so ingrossed in his book that he didn't hear the phone ring."
2. To write a formal document in a clear, legible hand: This is a more formal meaning, related to the historical practice of writing official documents in a large, ornate script. It's rarely used in everyday language.
* Example: "The lawyer ingrossed the contract before signing it."
It's important to pay attention to the context to understand which meaning of "ingrossed" is intended.