What does "strengthen" mean?

1. (to make physically stronger) to make something tougher or more solid so it does not break. 2. (to become stronger) to grow in power or intensity. 3. (to support an argument or belief) to make an idea or a feeling more certain or powerful. 4. (to improve a relationship or position) to make a connection between people or a position in a group more secure.

How do you use "strengthen"?

Often used with a direct object representing a body part or a physical structure. Intransitive use; the subject is often a natural force, a currency, or an abstract trend.

strengthen

US //ˈstɹɛŋθən// UK //stɹˈɛŋθən// strength·en

1 to make physically stronger (v.)
B1 Intermediate

to make something tougher or more solid so it does not break.

to increase the physical power, durability, or structural integrity of an object or body part.

Example

You can do these exercises every morning to strengthen your back muscles.

Example

The engineers decided to strengthen the bridge's support pillars with carbon fibre to ensure they could withstand the increased weight of modern traffic.

Usage

Often used with a direct object representing a body part or a physical structure.
- fortify
- reinforce
- toughen
- weaken
- enfeeble
2 to become stronger (v.)
B2 Upper Intermediate

to grow in power or intensity.

to increase in force, intensity, or power; used without a direct object.

Example

The wind began to strengthen as the storm moved closer to the coast.

Example

Economic indicators suggest that the local currency will continue to strengthen against the dollar throughout the next fiscal quarter.

Usage

Intransitive use; the subject is often a natural force, a currency, or an abstract trend.
- fade
- diminish

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3 to support an argument or belief (v.)
B2 Upper Intermediate

to make an idea or a feeling more certain or powerful.

to provide additional evidence or support to an argument, belief, or emotional state.

Example

The new evidence will strengthen our case in court tomorrow.

Example

The latest archaeological findings significantly strengthen the theory that the ancient settlement was a major trading hub rather than a simple military outpost.
- undermine
- disprove
4 to improve a relationship or position (v.)
B2 Upper Intermediate

to make a connection between people or a position in a group more secure.

to consolidate or improve the quality of a relationship, alliance, or strategic position.

Example

The two countries signed a new treaty to strengthen their friendship.

Example

The CEO's recent keynote address was designed to strengthen investor confidence following a period of significant market volatility.
- damage
- strain

Origin

From rare Middle English strengthenen (14th c.), from earlier strengthen (12th c.), where -en is the infinitive ending. Probably the original form was reinterpreted as strength + -en around the time when the infinitive ending was being apocopated in late Middle English.