When you need to express the idea of setting something aside for later use, there are a few different words and phrases you can use instead of "put aside." One option is "save," which implies that you are preserving something for future use or avoiding using it all at once. "Store" is another good option, suggesting that you are putting something away in a safe place for long-term storage. "Reserve" is another alternative, implying that you are setting something aside specifically for a particular purpose or occasion. Finally, you might use the phrase "set aside" itself, or look for synonyms like "dedicate" or "earmark.