The phrase "from side to side of" can be replaced with various synonyms. Some examples include "across," "over," "throughout," "all over," "from end to end," "from one side to the other," "covering," and "spanning." Each of these synonyms represents a slightly different shade of meaning, but they all convey the basic idea of something extending or moving across a particular area or distance. Whether you are writing a formal paper, a creative work, or even just a simple email, using synonyms can help you vary your language and communicate your ideas more effectively.