When it comes to describing something that's held in reserve, there are a number of different synonyms that can be used to convey a similar meaning. For instance, one might say something is "kept in store," "saved for later use," "put aside," or "set aside for a rainy day." Other synonyms might include "reserved," "held back," "retained," or "kept on hand." Each of these words can add a slightly different nuance to the phrase, depending on the context and the intent behind the reserve, but all share a common thread of indicating something held back or saved for a future moment.