The phrase "is contiguous" refers to things that are adjacent or touching each other. There are many synonyms that can be used in place of this phrase, depending on the context. Some alternatives include "is adjoining", "is neighboring", "is connected", "is bordering", "is touching", "is adjacent", "is abutting", "is alongside", "is conjoined", or "is attached". Each of these synonyms conveys the same meaning as "is contiguous", but with a slightly different emphasis or connotation. Choosing the right synonym can help to create more effective and engaging writing by adding variety, clarity, and interest.