The two are the same thing. As a double bass major in a conservatory, I should be qualified to answer your question.

The double bass is the tallest and largest violin among the bowed instruments in the symphony orchestra, and is also used as the original bass plucked instrument in the jazz band.

There are many confusing names for the double bass, and they are called differently in different situations.

Official name:

Chinese name: double bass

American name: doublebass, British name: contrabass, German name: kontrabass

Hong Kong and Taiwan: double bass

Mainland: double bass (double bass), big bass, double bass, wooden bass, box bass

Specific name:

Sound library: Acoustic Bass, Acoustic Bass

An interesting introduction about the double bass: the Chinese grandpa of string instruments is also an electric bass ancestors.