sim
Latinlike, same, similar
About This Root
The root sim / sem grows from one of the oldest Indo-European ideas: PIE sem-, meaning 'one' or 'together as one.' If two things are counted as one, they are the same; if they are merely close to being one, they are similar*. Latin took this seed and grew several branches.
similis meant 'like, resembling.' This is the workhorse of the family. Add suffixes and prefixes and a whole group of 'likeness' words appears:
- similis alone → similar, similarity: nearly the same
- simul- (the same form used as a verb stem) → simulate: to make something like the real thing, to feign or imitate; simulation, simulator, simulated follow directly
- ad- (to) + similis → assimilate: to make one thing like another and absorb it — a culture, a nutrient, an idea
- dis- (apart) + similis → dissimilar: not alike
simul meant 'at the same time, together.' From it comes simultaneous — two events sharing one moment.
A second, sound-shifted branch entered English through Old French as sembl- (from the same Latin similāre). Here the 's-i-m' softened to 's-e-m-b':
- re- (again, intensive) + sembl → resemble: to look like; resemblance is the noun
- as- (to) + sembl → assemble: literally 'to bring together into one,' giving assembled, assemblage, reassemble
- sembl alone → semblance: an outward likeness — often a mere appearance that hides the truth
- French en- + sembl → ensemble: a set of things taken 'together' as one whole
A third branch springs from sem- meaning 'one': simple comes from sem- + plex ('one fold'). Something folded only once is uncomplicated — hence simple, simply, simplicity, simplify, simplistic. And the frozen Latin command fac simile ('make it like!') gives facsimile, an exact copy.
One note on boundaries: Greek syn-/sym- ('together') — as in symbol, symphony, symmetry — entered English through Greek, not Latin, so those words live under their own roots. And the Germanic word same is a cognate cousin, inherited directly rather than borrowed.
The through-line: every member of this family circles the idea of 'one and the same' — being alike (similar), made alike (simulate, assimilate), brought into one (assemble, ensemble), or counted as one (same, simple).
Think of a flight simulator: it is built to be the same as the real cockpit. That core idea — 'same / like' — runs through every sim/sem word. similar = alike, assemble = bring into one, same = one and the same. When the spelling softens to sembl (resemble, ensemble), it is the same root wearing a French coat.
Core Words Deep Dive
The few words from this family worth telling in full — one by one.
simulateFrom Latin simulāre, 'to make like.' To simulate is to produce something that behaves *like* the real thing without being it — a flight simulator, a computer simulation.
From Latin simulāre, 'to make like.' To simulate is to produce something that behaves *like* the real thing without being it — a flight simulator, a computer simulation. The same stem hides a darker sense: to simulate an emotion is to *feign* it, to put on a likeness you don't truly feel. That tension between 'faithful imitation' and 'fake pretense' lives in the whole sub-family.
Open simulateassembleas- (to) + sembl (from similis, 'alike/together') = 'to bring alike things into one place.' The leap is from 'like' to 'gather': things that belong together are brought together.
as- (to) + sembl (from similis, 'alike/together') = 'to bring alike things into one place.' The leap is from 'like' to 'gather': things that belong together are brought together. Hence an assembly line literally puts parts into one whole, and a national assembly gathers people as one body.
Open assembleresemblere- (intensive) + sembl (be like) = 'to be very like.' It entered through Old French resembler, which is why the Latin -sim- softened to -semb-.
re- (intensive) + sembl (be like) = 'to be very like.' It entered through Old French resembler, which is why the Latin -sim- softened to -semb-. Note it is almost always transitive: X resembles Y (never 'resembles to'). The noun is resemblance.
Open resemblesimpleThe surprise member: simple comes from sem- ('one') + -plex ('fold') = 'one-fold.' Something folded only once has no hidden layers — it is plain, uncomplicated.
The surprise member: simple comes from sem- ('one') + -plex ('fold') = 'one-fold.' Something folded only once has no hidden layers — it is plain, uncomplicated. Contrast complex (com- 'together' + plex 'fold' = many folds woven together). So simple and complex are literally about how many times reality is folded.
Open simplesimultaneousFrom Latin simul ('at the same time').
From Latin simul ('at the same time'). Two things are simultaneous when they share one moment — the 'sameness' is in time, not appearance. This is the time branch of the root, distinct from the 'likeness' branch (similar). Common in 'simultaneous translation' and, in math, 'simultaneous equations.'
Open simultaneousRelated Roots
Greek homo- also means 'same' (homogeneous, homonym). It is a synonym in meaning: homo- comes from Greek homos, while sim comes from Latin similis. Both are useful 'sameness' markers — homo- tends to be technical/scientific, sim more everyday.
Greek syn-/sym- ('together': synthesis, symphony, sympathy) came into English through Greek instead of Latin. So symbol and assemble both carry the image of 'brought together,' yet they live under different roots in English.
Associated Words · 56
same
identical; not changed
simply
in a straightforward way; merely; completely
similar
having likeness to something else; nearly the same
simple
easy to do or understand; not complicated
similarly
In the same or a comparable way
resemble
To look like or be similar to someone or something
assemble
To gather together; to put parts together
simultaneously
At the same time
assembly
A gathering of people; the fitting together of parts
similarity
The quality of being alike or resembling something else
ensemble
A group performing together; a coordinated set forming a whole
simulation
An imitation of a real system or process for study or training
simplicity
The quality of being plain, uncomplicated, or easy to understand
resemblance
Similarity in appearance or nature
simulate
To imitate or reproduce the behavior or conditions of something
simplify
To make something less complex or easier to understand
simultaneous
Happening or done at exactly the same time
assimilation
The process of absorbing and integrating people, ideas, or nutrients
assimilate
To absorb information or nutrients; to integrate into a culture
simplistic
Misleadingly oversimplified; treating complex issues as simple
assemblage
A collection of things or people gathered together
simulator
A machine or program that imitates a real environment for training
semblance
An outward appearance that may not reflect reality
simplified
Made easier by reducing complexity