Mass
Mass is a measurement of the quantity of matter in a physical object.

In 2266, the sensors of the  read the mass of an alien cube as little under 11,000 metric tons. Later, the sensors were unable to read the mass of the Fesarius as it went off the scale. ()

Mass was an important measurement to understand Changeling physiology. Odo was under significant study in his early life, and Julian Bashir noted that Odo's mass was similar whenever he was in humanoid form, and changed when he changed shape. When he suffered a poison from his people in 2372, Bashir first noted that Odo's mass fluctuated rapidly. ()

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Physics