Gross has several meanings:

1. Something disgusting or unpleasant. When you find moldy food in the back of the refrigerator, you might say “That's gross!” A gross smell, gross habit, or gross insect makes you wrinkle your nose or look away. What seems gross varies from person to person: some kids think Brussels sprouts are gross, while others love them.
2. Very obvious or extreme. A gross exaggeration makes something sound way bigger or worse than it really is. If someone makes a gross error in math, they didn't just miss by a little, they got the answer completely wrong. Gross injustice means unfairness so clear that anyone can see it.
3. The total amount before anything is subtracted. A store's gross income is all the money it takes in before paying for rent, supplies, and salaries. Your gross weight includes your clothes and shoes, while your net weight doesn't. Think of gross as the big starting number.
4. A unit of measurement equal to 144 items (twelve dozen). If a factory ships a gross of pencils, that's exactly 144 pencils. This meaning is less common today but still used in manufacturing and wholesale.