similar

The word 'similar' descends from the concept of oneness.‌​‍​‍​‌​‌​‍​‌​‌​‌​‍​‌​‌​‍​‌​‍​‍​‍​‍​‍​‌​‌​‍​‍​‌​‌​‌​‌​‍​‌​‍​‍​‌ Latin 'similis' (like, resembling) traces back to the Proto-Indo-European root *sem-, meaning 'one' or 'together.' The underlying logic is that things which are similar share a quality of oneness — they are, in some essential way, 'as one.' This connection between likeness and unity runs deep in Indo-European thought.

Latin 'similis' may have developed from an earlier form *semilis, directly from the root *sem-. The same root produced Latin 'simul' (together, at the same time — source of English 'simultaneous' and 'simulate'), 'semel' (once, at one time), and 'simplex' (one-fold, straightforward — source of English 'simple'). The semantic range — oneness, togetherness, likeness, simplicity — reveals how the PIE speakers conceived of similarity: things that are alike are, at a deep level, one thing.

The Germanic branch of *sem- produced Proto-Germanic *samaz (same), which entered English primarily through Old Norse 'samr' (same), giving Modern English 'same.' The Greek branch produced 'homos' (ὁμός, same, one and the same), the source of the prefix 'homo-' in 'homogeneous' (of the same kind), 'homosexual' (of the same sex), 'homonym' (of the same name), and the combining form 'homoio-' in 'homoiopatheia' (suffering the same thing — source of 'homeopathy'). Sanskrit received 'sama' (same, equal).

English borrowed 'similar' from French 'similaire' in the early seventeenth century. The word filled a gap between 'same' (identical) and 'like' (general resemblance). 'Similar' occupies a precise middle ground: things that are similar share important features but are not identical. This precision makes the word essential in scientific, mathematical, and legal discourse.

In geometry, 'similar' has a technical definition: two figures are similar if they have the same shape but not necessarily the same size. Similar triangles have equal angles but proportional sides. This mathematical sense — likeness of form despite difference of scale — captures the word's etymology perfectly: similar things are 'as one' in form, even if they differ in magnitude.

In law, 'similar fact evidence' (or 'similar acts evidence') refers to evidence from previous incidents that resembles the current case closely enough to be relevant. The legal concept requires careful definition of what counts as 'similar' — a problem that reveals the word's inherent vagueness when precision is needed.

The literary term 'simile' — a comparison using 'like' or 'as' — comes from the neuter form of Latin 'similis.' A simile is a figure of speech that makes similarity explicit: 'life is like a box of chocolates,' 'her eyes shone like stars.' The related rhetorical device of 'similitude' extends the comparison into a sustained analogy.

The verb 'simulate' (from Latin 'simulāre,' to make similar, to imitate) and its derivatives — 'simulation,' 'simulator,' 'simulacrum' — belong to the same family. A simulation creates a likeness of reality; a simulacrum is an image or representation. The modern concept of computer simulation extends this ancient idea of creating something similar to reality into digital domains.

'Resemble' (from Old French 'resembler,' from 're-' + 'sembler,' to seem like) also connects to this root through a different etymological path. 'Ensemble' (French for 'together,' from Latin 'insimul') — used in music for a group performing together — carries the 'togetherness' sense of the PIE root.

From PIE *sem- through Latin 'similis' to modern 'similar,' the word preserves one of language's most fundamental conceptual operations: recognizing that different things can share essential qualities — that the world, despite its diversity, contains patterns of likeness that bind separate entities into groups, categories, and kinds.