A decimal system is a type of numerical system that uses a base of ten, where each digit represents a certain power of ten. If you're looking for synonyms for the term "decimal system," there are a few options to consider. For instance, you could use the term "base ten," which refers to the same concept. Other possibilities include "denary system," "decimal notation," or "decimal arithmetic." Each of these terms refers to the same fundamental idea of using a system of ten digits to represent numerical values. Whether you're doing math or simply trying to describe this type of system, these synonyms can come in handy.