Incorrect spelling, explanation: there is no such word as strenght in Engish; it is a misspelling. The correct form is strength as it is a noun form from the adjective strong to which we added suffix -th. Old English and Middle English forms also point to strength as the correct spelling (strengthu, strengthe).

Correct spelling, explanation: strength is the correct spelling and a noun form from the adjective strong. To create such noun suffix -th is added (like long→ length. In Old English, the word was spelled strengthu. This points to strength as a correct form; strenght is a misspelling.

Definition of strength:
noun, power, force, quality of being strong
They couldn’t call us via radio because the signal strength was poor.
She had the strength to admit she was addicted.

Idioms and phrases with strength
on the strength of, relying on:
They introduced changes in their politics on the strength of the new law.

Incorrect spelling

Incorrect spelling

Incorrect spelling