strengthen-v; 2 Senses

Sense Number 1: to fortify,reinforce, make strong

Commentary: Syntax is: NP1[agent] STRENGTHEN NP2[patient]

The trade agreement strengthened ties between the nations.
The good nutrition will help to strengthen his immune system.
These additives strengthen the steel.

VerbNet: other_cos-45.4
FrameNet: Cause_change_of_strength
PropBank: strengthen.01
WordNet 3.0 Sense Numbers: 1, 3

Sense Number 2: gain strength or resilience

Commentary: Syntax is: NP1 STRENGTHEN (PP[instrument])

The hurricane strengthened over the ocean.
The town's opposition to the new mall is strengthening.

VerbNet: other_cos-45.4
FrameNet: NM
PropBank: NM
WordNet 3.0 Sense Numbers: 2