Mosaic plagiarism occurs when a student borrows phrases from a source without using quotation marks, or finds synonyms for the author’s language while keeping to the same general language structure and meaning as found in the original.
Sometimes called “path writing,” this kind of plagiarism, whether intentional or not, is academically dishonest and punishable. Even if you footnote your source.
from QC Pages of CUNY
In plainer language, it’s basically copying by concept with key point level details rather than by word, sentence, or paragraph. You could think of it as using “Replace All” for all names, maybe a few common, often used, words, expressions, used in the text, then rewriting sentences or paragraphs at a time in your own words, as a fast way of doing this.
In another way of possibly doing this where the “path writing” name might have come from, think of the plot as a path from start to end. Along the way, you pass through key points along the path. If you work harder than the example I gave in the paragraph above, you’d then be writing a summary to identify all these key points, change some names, and basically write your way from point to point, with the points being not too far apart so as not to lose the integrity of the original story that might have made it appealing. That is, some level of details, just enough not to get sued easily for plagiarism.