Weight was the mass of a person or object. It could be affected by gravity.
Weight of individuals 
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Harry Mudd's weight
Those whose weights exceeded normal measurements were said to be overweight. (TNG: "The Outrageous Okona"; VOY: "Critical Care")
As of 2266, Harry Mudd weighed 240 pounds. (TOS: "Mudd's Women")
As of 2370, Data weighed 100 kilograms. (TNG: "Inheritance") Of that weight, 26.8 kilos was of tripolymer composites, 11.8 kilos was of molybdenum-cobalt alloy, and 1.3 kilos was bioplast sheeting. (TNG: "The Most Toys")
Kor felt insecure about how heavy he was because he was lighter when he had last seen Dax. (DS9: "Blood Oath")
When the crew of the USS Voyager was trapped in The Void, Kathryn Janeway wondered if they would lose weight due to malnutrition. (VOY: "The Void")
Weight of objects Edit
In 2370, when Jadzia Dax requested a bat'leth from the holosuite, she specified it to weigh five point three kilos. (DS9: "Blood Oath")
In 2378, B'Elanna Torres played The Doctor's holonovel entitled Photons Be Free in the role of an emergency medical technician. Her character's mobile emitter was much heavier and bulkier than the one in reality and she speculated it must have weighed fifty kilos. When she asked The Doctor about it, he said that its weight served as a metaphor for the burden of being a hologram. (VOY: "Author, Author")
