Similar, a.
Etymology: [F. similaire, fr. L. similis like, similar. See Same, a., and cf. Simulate.]
1. Exactly corresponding; resembling in all respects; precisely like.
2. Nearly corresponding; resembling in many respects; somewhat like; having a general likeness.
3. Homogenous; uniform. [R.] Boyle. Similar figures (Geom.), figures which differ from each other only in magnitude, being made up of the same number of like parts similarly situated. -- Similar rectilineal figures, such as have their several angles respectively equal, each to each, and their sides about the equal angles proportional. -- Similar solids, such as are contained by the same number of similar planes, similarly situated, and having like inclination to one another.
1 other Webster entry under this spelling
Similar, n.
That which is similar to, or resembles, something else, as in quality, form, etc.
Shades of meaning
Fernald has no entry of its own for similar; he lists it under alike, synonymous.
Where he writes about it:
Similar refers to close resemblance, which yet leaves room for question or denial of complete likeness or identity. — from alike
To say "this is the identical man," is to say not merely that he is similar to the one I have in mind, but that he is the very same person. — from alike
Things are analogous when they are similar in idea, plan, use, or character, tho perhaps quite unlike in appearance; as, the gills of fishes are said to be analogous to the lungs in terrestrial animals. — from alike
To consider synonymous words identical is fatal to accuracy; to forget that they are similar, to some extent equivalent, and sometimes interchangeable, is destructive of freedom and variety. — from synonymous