The term "orthologous gene" refers to genes that have evolved from a common ancestor and have similar functions in different species. Other words that can be used as synonyms for orthologous gene include homologous genes, equivalent genes, and conserved genes. Homologous genes also refer to genes that share a common ancestor, whereas equivalent genes indicate that the gene functions are similar. Conserved genes, on the other hand, refer to genes that have been maintained over time due to their importance and similarity in different species. The use of these synonyms helps in describing the evolutionary relationships between different species and their biological functions.