What is the difference between "開ける", "空く", "打ち解ける", "散開星団", "公開市場操作"?

"開ける" means "to open (something)", "空く" means "to open, to be vacant, to be available, to become empty", "打ち解ける" means "to open one's heart, to become friendly, to relax", "散開星団" means "Open cluster", "公開市場操作" means "Open Market Operations".

Quintuple VS

Synonym Boundary: "開ける", "空く", "打ち解ける", "散開星団", "公開市場操作"

All represent the core concept "open", but require precise selection.

Japanese Option A

開ける

あける (akeru)

N5 / CEFR

Japanese Option B

空く

あく (aku)

N4 / CEFR

Japanese Option C

打ち解ける

うちとける (uchitokeru)

N2 / CEFR

Japanese Option D

散開星団

さんかいせいだん (sankaiseidan)

C2 / CEFR

Japanese Option E

公開市場操作

こうかいしじょうそうさ (koukaishijousousa)

C2 / CEFR

Quintuple VS Nuance Contrast & Social Differences

When expressing "open" in Japanese, you must carefully distinguish between "開ける", "空く", "打ち解ける", "散開星団", "公開市場操作" based on context.

開ける (あける (akeru) - Level: N5): Maps to "to open (something)" and is used when Transitive verb.
空く (あく (aku) - Level: N4): Maps to "to open, to be vacant, to be available, to become empty" and is used when An intransitive verb. Refers to something becoming empty, available, or a space opening up. For example, 席が空く.
打ち解ける (うちとける (uchitokeru) - Level: N2): Maps to "to open one's heart, to become friendly, to relax" and is used when To become less reserved, more relaxed and informal with someone, moving from a formal or tense state to a more comfortable and open one. Often used with the particle 「に」..
散開星団 (さんかいせいだん (sankaiseidan) - Level: C2): Maps to "Open cluster" and is used when Essential structural term in CEFR C2 vocabulary syllabus..
公開市場操作 (こうかいしじょうそうさ (koukaishijousousa) - Level: C2): Maps to "Open Market Operations" and is used when Essential structural term in CEFR C2 vocabulary syllabus..

Mixing these up can easily lead to unnatural translations. Refer to the bilingual context cards below to master the boundaries!

Context for "開ける"

ドアを開けてください。

Please open the door.

Context for "空く"

会議室が空いていますか。

Is the meeting room available?

Context for "打ち解ける"

彼はどんな人ともすぐに打ち解けることができる。

He can quickly become friendly with anyone.

Context for "散開星団"

私は散開星団に興味があります。

I am interested in Open cluster.

Context for "公開市場操作"

私は公開市場操作に興味があります。

I am interested in Open Market Operations.

Synonym Mastery Challenge

Which Japanese word perfectly fits this blank space?

Fill in the blank: "ドアを開けてください。" (Meaning: "Please open the door.")

🎉 Correct Answer!

Remember: "開ける" is correct here because it represents "to open (something)" in the context: "Please open the door.".