The phrase "one specialty" refers to a specific area or field in which an individual or organization excels. There are numerous synonyms for this phrase, including "specialization," "expertise," "forte," "strength," "advantage," "mastery," "proficiency," "skill," "talent," and "capability." All of these words suggest a unique skill set that sets an individual or organization apart from others in their respective fields. Whether it is a particular trade, industry, or subject matter, each of these synonyms highlights the importance of having a specific area of focus, and the benefits that come with mastering that area.