Is tooth means one or more?

The answer is "one".

The word "tooth" can be used to refer to a single tooth or to multiple teeth. However, when the word "tooth" is used without a specifier, it is usually interpreted as meaning one tooth. This is because in most cases, people are more likely to be talking about a single tooth than multiple teeth.

For example, if someone says that they have a toothache, they are most likely referring to a pain in one tooth, rather than pain in multiple teeth. Similarly, if someone says that they need to get a tooth fixed, they are most likely referring to a problem with one tooth, rather than multiple teeth.

Of course, there are exceptions to this rule. For example, if someone says that they have "bad teeth," they are most likely referring to multiple teeth that are affected by a problem, such as cavities or gum disease. However, in most cases, the word "tooth" is interpreted as meaning one tooth when it is used without a specifier.