If two things are analogous, they are similar in a useful way, so you can compare them and learn something. We do not mean they are the same; we mean they work alike, or share a pattern. You might say a city’s traffic is analogous to blood moving through a body: different stuff, similar job. It is a fairly formal, school-and-essay word. In biology there is a tighter sense, nearly as old as the general one: analogous parts of animals look or work alike but did not come from the same ancestral part (a bird’s wing and a butterfly’s wing). Scientists contrast that with homologous, which means the parts do share an origin. Everyday speakers often skip this contrast and just mean “similar enough to compare.”