1. To place something on someone. I covered my daughter in a thick blanket before leaving her hospital room.

2. To coat something in something. We need to cover this whole wall in the gray paint.

3. To become coated in something. In this usage, "cover" is often used in the past tense without a noun or pronoun between "cover" and "in." After hours of gardening, Eva was covered in dirt. I was quickly covered in blood after the ball hit me in the face.