重さ（おもさ、omosa）
- weight

The Japanese word 重さ (おもさ) means "weight" or "heaviness." It refers to how heavy something is. It's a noun. It represents the degree of being heavy. The word describes the quantity of something. The word 重さ can also be used figuratively to express the importance or significance of something.

⚫︎このリンゴの重さはどのくらいですか。 ・Translation: How much does this apple weigh? ⚫︎彼女は、人生の重さを感じている。 ・Translation: She feels the weight of life. ⚫︎その荷物の重さを量る。 ・Translation: To measure the weight of that luggage.

You can use 重さ in various situations: ⚫︎ When you're talking about the physical weight of an object. ⚫︎ When discussing the burden, importance, or seriousness of something (figuratively). ⚫︎ When asking about the weight of something. ⚫︎ When expressing the physical force exerted by an object due to gravity.

重さ is primarily written in kanji. The hiragana reading is おもさ. There are no other common ways to write this word. The okurigana (送りがな, the hiragana that follows the kanji) is typically さ.

⚫︎ 質量 (しつりょう) - Mass (physics-related, very technical). ⚫︎ 重量 (じゅうりょう) - Weight (formal or technical term). ⚫︎ 重み (おもみ) - Heaviness (another word for weight). ⚫︎ 負担 (ふたん) - Burden (used for the figurative sense).

⚫︎ 軽さ (かるさ) - Lightness (opposite of weight).

この箱の重さは五キログラムです。 ・Translation: The weight of this box is five kilograms. ・Explanation: This sentence describes the physical weight of the box.

彼女は責任の重さを感じている。 ・Translation: She feels the weight of responsibility. ・Explanation: This sentence uses 重さ in a figurative sense, referring to the burden of responsibility.

The word 重さ is derived from the adjective 重い (おもい), meaning "heavy". The suffix さ (-sa) is added to many adjectives to form nouns representing the degree or state of the adjective. Therefore, the word 重さ is created to express the degree of being "heavy".