Obsoletisms are outdated words or phrases that are no longer in popular use. There are many synonyms for this term, including archaisms, antiquated words, obsolete expressions, and outdated language. These words and phrases were commonly used in the past but have fallen out of favor or been replaced by newer terminology. Some examples of obsoletisms include terms like "icebox," "telegraph," and "phonograph." While these words may have had meaning and importance in their time, they are now considered old-fashioned and irrelevant to modern society. As language and technology continue to evolve, it is likely that more obsoletisms will fall out of use and be replaced by newer, more relevant terminology.