General term for how much a container, space, or system can hold; also used for data storage, battery charge, and abstract capacity.
This battery has a capacity of 5000mAh.
I'm running out of space on my hard disk.
This hard disk has a large capacity.
The file size exceeded the storage capacity.
My phone's storage became full.
I increased the memory capacity.
容量 means capacity or volume, not weight, but its similar sound and kanji ending can make it easy to mix up with 重量.
heat capacity
variable capacity; variable capacitance