Explanation
Units of Mass
Mass is a measure of the amount of matter in an object. The units used to measure mass include:
 Kilogram (kg): The metric unit for mass and the base unit in the International System of Units (SI).
 Gram (g): A smaller metric unit for mass, where $1 \, \text{kg} = 1000 \, \text{g}$.
 Milligram (mg): An even smaller metric unit, where $1 \, \text{g} = 1000 \, \text{mg}$.
 Metric Ton (t): Larger mass unit, where $1 \, \text{t} = 1000 \, \text{kg}$.
Other common units of mass in different systems include:
 Pound (lb): Used primarily in the United States, where $1 \, \text{lb} \approx 0.453592 \, \text{kg}$.
 Ounce (oz): Also used in the US, where $1 \, \text{oz} = \frac{1}{16} \, \text{lb}$.
Units of Weight
Weight is the force exerted by gravity on an object. The units used to measure weight are often the same as those for mass but consider the gravitational force. Common units include:

Newton (N): The SI unit of force, where weight $W$ is calculated as $W = mg$ with:
$W = m \cdot g$Here, $m$ is the mass in kilograms and $g$ is the acceleration due to gravity ($9.81 \, \text{m/s}^2$).

Dyne: A unit in the CGS (centimetergramsecond) system, where $1 \, \text{N} = 10^5 \, \text{dynes}$.
In nonmetric systems:
 Poundforce (lbf): In the US customary system, this is equivalent to the gravitational force on a pound mass under standard gravity, $1 \, \text{lbf} \approx 4.44822 \, \text{N}$.
Summary: the primary units of mass are kilogram (kg), gram (g), and pound (lb), while the main units of weight are Newton (N) and poundforce (lbf).