1.
weight; heaviness
The physical weight of an object, or how heavy something feels. Formed from the adjective 重い by adding the suffix ～さ.
この荷物の重さはどのくらいですか。
How much does this luggage weigh?
重さを量ってから送料を計算する。
We calculate the shipping cost after weighing it.
この箱は見た目より重さがある。
This box is heavier than it looks.
2.
weight; gravity; significance
The figurative weight or seriousness of something, such as responsibility, words, or a situation.
責任の重さを感じる。
I feel the weight of responsibility.
彼の言葉には重さがあった。
His words carried weight.
命の重さは誰にとっても同じだ。
The weight of life is the same for everyone.
Formed from the i-adjective 重い (heavy) plus the nominalizing suffix ～さ, which converts adjectives into nouns expressing degree or extent.
COMMON COLLOCATIONS:
- 重さを量る (to weigh, to measure the weight)
- 重さがある (to have weight, to be heavy)
- 責任の重さ (the weight of responsibility)
- 言葉の重さ (the weight of words)
- 命の重さ (the weight/value of life)
Do not confuse with 重み, which also means "weight" but emphasizes dignity, gravitas, or significance rather than physical mass. 重さ is the more general term for both physical and figurative weight.