When writing a patent, some words need to be explained. Are they explained in the explanation?

See if the term is widely known, if it is, it is unnecessary; If not, you must. Of course, to be on the safe side, it is best to explain everything in the instructions as clearly as possible. Relevant clauses are quoted as follows:

The specification shall use technical terms in the technical field to which the invention or utility model belongs. For natural science terminology, if the state has provisions, unified terminology should be adopted; If there are no regulations in the country, established technical terms can be adopted, little-known or up-to-date scientific terms can be adopted, and foreign words (transliteration or free translation of Chinese words) can be directly used, but their meanings must be clear to technicians in the technical field and will not cause misunderstanding; You can use custom words if necessary. In this case, a clear definition or explanation should be given. Generally speaking, we should not use words with the basic meaning in the technical field to express other meaning beyond its original intention, so as to avoid misunderstanding and semantic confusion. Technical terms and symbols used in the manual should be consistent.