Small picky bit but ounces are a measure of weight and grams are a measure of mass. Not exactly the same thing but most people in the US consider metric grams and kilograms to be weight.

English system:
weight - pounds, ounces.
Mass - Slug, 1 slug has a weight of 32 pounds

Metric:
Weight - Newton
Mass - Kilogram, 1 killogram has a weight of 9.8 newtons (at sea level)