A more thorough explanation:

A descriptive trademark is a type of trademark that is a meaningful word in common usage or that merely describes or suggests a product. This type of trademark is entitled to protection only if it has acquired distinctiveness over time.

For example, "Apple" is a descriptive trademark for a company that sells computers and electronic devices. The word "apple" is a common word in the English language, but it has acquired distinctiveness over time as a trademark for this particular company. Another example is "Holiday Inn" which describes a hotel that is open during holidays.

Descriptive trademarks are considered weak trademarks because they do not have inherent distinctiveness and are not entitled to strong legal protection. However, if a descriptive trademark has acquired distinctiveness over time through extensive use and promotion, it may be eligible for trademark protection.