Specific gravity or relative density: the ratio of a substance's density to that of a reference (usually water).
鉄の比重は約7.87で、水より重い材料だ。
The specific gravity of iron is about 7.87; it is heavier than water.
比重計を使って液体の比重を測定した。
I measured the specific gravity of the liquid using a hydrometer.
溶液の比重が基準値を超えていることがわかった。
It turned out that the solution's specific gravity exceeded the standard value.
Relative importance or weight: how much significance or proportion an element has within a whole.
このプロジェクトでは品質に比重を置いて進めたい。
In this project we want to place more weight on quality.
高齢者の割合が増え、人口構成の比重が変化している。
With an increasing proportion of elderly people, the population composition's weight is changing.
売上だけでなく、顧客満足の比重も重要だ。
Not only sales but also the weight given to customer satisfaction is important.