An interaction between bodies due to their mass. Weight is the force of gravity acting on an object.

Derive formula from free fall thought experiment.

W = m g

Things that weigh a newton. One newton is about halfway between one-fifth and one-fourth of a pound or the weight of one hundred grams.

1 N ≈  101.972 gf or 0.101972 kgf
1 N ≈  0.224809 lb or 3.59694 oz

The "acceleration due to gravity" is also equal to the "gravitational field". Equivalence of inertial and gravitational mass.

Weight is the effect on objects of the acceleration of a reference frame?