When it comes to describing "lid number", several synonyms can be used to add variety and precision to your language. One possible synonym is "cap number", which captures the essence of an identifying code associated with a cap or cover. Another alternative is "top number", highlighting the numerical identifier affixed to a lid or surface. Additionally, "closure number" can be employed to emphasize the concept of a designated numerical label related to a sealing mechanism. Lastly, "cover digit" offers a concise and distinct synonym for a numeric symbol assigned to a lid or protective covering. Utilizing these synonyms can enrich your vocabulary and provide alternative ways to describe a "lid number."