Translation guide
The English verb 'strengthen' covers making something physically stronger, reinforcing structures, intensifying feelings or resolve, and bolstering arguments or relationships. Japanese uses different verbs depending on what is being strengthened and whether the change is physical, abstract, or metaphorical.
To increase physical strength, fitness, or robustness of a person, animal, or body part.
To train, discipline, or forge the body or mind through effort. Commonly used for muscles, skills, or mental fortitude.
毎日ジムで体を鍛えています。
I strengthen my body at the gym every day.
腕立て伏せで腕を鍛える。
I strengthen my arms with push-ups.
A general phrase meaning 'to make strong'. Can be used for muscles, but 鍛える is more natural for intentional training.
この運動は足を強くします。
This exercise strengthens your legs.
To strengthen, reinforce, or enhance. Often used in formal or technical contexts, including physical training programs.
体幹を強化するトレーニング
training to strengthen the core
To make a building, bridge, material, or physical object stronger or more resistant to force.
To reinforce, shore up, or add strength to a structure. Used for buildings, walls, bridges, etc.
地震に備えて家を補強した。
We strengthened the house in preparation for earthquakes.
橋の支柱を補強する工事
construction work to strengthen the bridge supports
Also used for structural strengthening, often in technical or official contexts.
建物の耐震性を強化する。
Strengthen the earthquake resistance of the building.
To make something sturdy or durable. More casual and less technical than 補強する.
この棚をもっと丈夫にしたい。
I want to strengthen this shelf.
To make an emotion, determination, belief, or relationship stronger.
Transitive verb meaning to intensify or strengthen something abstract like feelings, impressions, or influence.
彼の言葉が私の決心を強めた。
His words strengthened my resolve.
その事件は人々の不安を強めた。
The incident strengthened people's anxiety.
To deepen (a relationship, understanding, bond). Often used for mutual connections.
To solidify or firm up (resolve, determination, plans). Implies making something firm and unshakable.
Used for abstract strengthening in formal contexts, like policies, systems, or security.
セキュリティを強化する必要がある。
We need to strengthen security.
To make a case, theory, or claim more convincing or robust.
To reinforce or back up an argument with additional evidence or reasoning.
新しいデータで仮説を補強した。
We strengthened the hypothesis with new data.
To make something firm or solid, often used for positions or stances.
証言が彼の立場を強固にした。
The testimony strengthened his position.
To support or corroborate with evidence. Often used in academic or investigative contexts.
To make a group, system, or skill more effective or powerful.
The standard term for strengthening organizations, teams, systems, or capabilities.
チームの連携を強化する。
Strengthen the team's cooperation.
会社は海外事業を強化している。
The company is strengthening its overseas operations.
To augment or build up, especially military forces, personnel, or resources.
軍隊を増強する。
Strengthen the military forces.
強める (tsuyomeru) is for abstract intensity (feelings, influence). 強化する (kyōka suru) is a formal, all-purpose 'strengthen' for systems, security, capabilities. 補強する (hokyō suru) is for physical reinforcement or backing up arguments with evidence.
While 強くする (tsuyoku suru) can mean 'make strong', it sounds unnatural for emotions or arguments. Use 強める or 強化する instead.
交流を通じて友情を深めた。
We strengthened our friendship through interaction.
決意を固めて留学した。
I strengthened my resolve and studied abroad.
この事実が彼の主張を裏付けている。
This fact strengthens his claim.