Synonyms for Capacity (same or very similar meaning)
WordNet sense 1 (the susceptibility of something to a particular treatment):
capability
WordNet sense 2 (the amount that can be contained):
content, content
WordNet sense 3 (an electrical phenomenon whereby an electric charge is stored):
capacitance, electrical capacity
WordNet sense 4 (the power to learn or retain knowledge; in law, the ability to understand the facts and significance of your behavior):
mental ability
From the ODE community, based on WordNet
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