1. One of two organs or parts in different species of animals or plants which differ in structure or development but are similar in function.
2. A compound that resembles another in structure but is not necessarily an isomer (e.g., 5-fluorouracil is an analog of thymine); analogs are often used to block enzymatic reactions by combining with enzymes (e.g., isopropyl thiogalactoside vs. Lactose).
Origin: g. Analogos, proportionate