What is the measure of mass for atoms commonly referred to as?

The measure of mass for atoms is commonly referred to as a Dalton. The Dalton is a unit of mass that is specifically used to express atomic and molecular weights. One Dalton is defined as one twelfth of the mass of a carbon-12 atom, making it a convenient unit for describing the mass of individual atoms and molecules in the context of chemistry and biology.

Using the Dalton helps in comparing the masses of different atoms and molecules on a relative scale, which is more practical than using larger units like grams, which are more suited for measuring macroscopic quantities. The other options, such as gram, pound, and ounce, are all units typically used for larger quantities of matter and not specialized for the atomic scale. This distinction highlights why the Dalton, as a unit specifically designated for atomic mass, is the correct answer.