cern
Latinto sift, separate, distinguish, decide
About This Root
Picture a Roman farmer holding a sieve, shaking it so the good grain falls through and the chaff stays behind. That physical act of sorting is the literal meaning of Latin cernere: to sift, to separate. From there the Romans made a leap that shaped a whole family of English words — they used the same verb for what the mind does. To sift evidence is to weigh it; to separate truth from falsehood is to judge; to settle a matter is to decide. So cernere came to mean "distinguish, perceive, decide" all at once.
The past participle was crētus, which is why the family shows two stems in English: cern- and cret-.
Attach prefixes and the sifting metaphor branches out:
- dis- (apart) + cernere → discern: to sift things apart with the eye or mind = to make out, to tell apart. From the cret- stem come discrete (sifted apart = individually separate) and its twin discretion / discreet (the power to sift apart in judgment = good judgment, carefulness).
- con- (together) + cernere → concern: literally to sift together, to mix in — and what is mixed into your affairs concerns you. The sense slid from "relate to" to "matter to" to "worry."
- se- (apart, aside) + cernere → secret: something sifted aside and set apart from others = hidden. The verb secrete kept two of those threads: to set a substance apart out of the body (a gland's secretion), and, more rarely, to hide something away.
- ex- (out) + cernere → excrete: to sift out of the body = to discharge waste; the noun excrement is what is sifted out.
Notice the surprise pair English inherited: discrete (separate, distinct) and discreet (careful, tactful) sound identical and come from the same Latin word — they were one word in Middle English that later split spellings to keep the two senses apart. The shared origin makes sense once you see the sieve: to keep something separate (discrete) and to keep a confidence to yourself (discreet) are both about careful separation.
The through-line for the whole family: every cern / cret word is some kind of separating or judging — telling apart, setting aside, sorting out, deciding.
Picture a sieve sorting grain from chaff — that's cernere, "to sift apart." Every cern/cret word is a kind of separating: discern (sift apart with your eyes = tell apart), secret (sifted aside = hidden), discrete (sifted into separate pieces), excrete (sift out of the body).
Core Words Deep Dive
The few words from this family worth telling in full — one by one.
discernThe most literal survivor of the sieve metaphor: dis- (apart) + cernere (sift) = to sift apart with the eyes or mind, i.e.
The most literal survivor of the sieve metaphor: dis- (apart) + cernere (sift) = to sift apart with the eyes or mind, i.e. to make something out or tell two things apart. You discern a shape in fog (perceive) or discern right from wrong (distinguish). It is formal and bookish — in casual speech people say "make out" or "tell apart."
Open discernconcernThe biggest semantic jump in the family.
The biggest semantic jump in the family. con- (together) + cernere (sift) = to sift together, to mix in. What gets mixed into your affairs "concerns" you — first just "relates to," then "matters to," and finally "worries." That is how one word covers "This concerns your future" (relates to), "a matter of concern" (importance), and "I'm concerned" (worried).
Open concernsecretse- (apart, aside) + cernere (sift) = sifted aside, set apart from everyone else = hidden.
se- (apart, aside) + cernere (sift) = sifted aside, set apart from everyone else = hidden. The image is one thing pulled out of the pile and kept separate. The same se- + cret- stem gives secretary (originally one entrusted with secrets) and secrete (to set a substance apart out of the body).
Open secretdiscreteFrom the cret- stem: dis- (apart) + crētus (sifted) = sifted into separate pieces = individually distinct, not continuous (discrete data, discrete units).
From the cret- stem: dis- (apart) + crētus (sifted) = sifted into separate pieces = individually distinct, not continuous (discrete data, discrete units). Its identical-sounding twin discreet (careful, tactful) is the SAME Latin word — Middle English spelled them alike, then split the spelling to keep the "separate" and "prudent" senses apart.
Open discreteexcreteex- (out) + crētus (sifted) = to sift out of the body = to discharge waste.
ex- (out) + crētus (sifted) = to sift out of the body = to discharge waste. The body acts like a sieve, separating what it keeps from what it expels. The matter sifted out is excrement; the cleaner medical noun is excretion.
Open excreteRelated Roots
Same Latin family. crīmen (charge, crime) originally meant "a decision, a judgment" — it comes from the same cernere root (to sift, judge). A crime is literally "the thing judged." So discern (to judge) and crime (the verdict of judgment) are distant cousins.
Also from cernere. certus ("settled, sure") is the past participle sense of cernere — once a matter has been sifted and decided, it is certain. So cert (certain, certify) is the "decided" branch of the same sieve metaphor that gives cern its "distinguish" sense.
Associated Words · 28
concern
To relate or belong to; to have reference to or connection with; to affect the interest of; to be of importance to; That which affects one’s welfare or happiness. A matter of interest to someone. The adposition before the matter of interest is usually over, about or for
secret
Information kept hidden from others; not known or revealed
secretary
A person handling clerical work; the head of a government department
secretly
In a hidden or covert manner
discretion
Careful judgment and tact; freedom to decide as one sees fit
discern
To perceive or distinguish something with the senses or mind
discrete
Individually separate and distinct; not continuous
discreet
Careful and tactful, avoiding embarrassment or unwanted attention
secretive
Tending to hide information or keep things secret
discretionary
Left to one's own judgment or choice
discernible
Able to be perceived or distinguished
discreetly
In a careful, tactful way that avoids drawing attention
secrete
To produce and release a substance from a gland; to hide
secretion
A substance released by a gland; the process of releasing it
discernment
The ability to judge and understand things clearly
excrete
To discharge waste from the body
excrement
Solid waste discharged from the body; feces
secretarial
Relating to the work of a secretary
indiscreet
Lacking caution or good judgment in speech or behavior
discretely
As separate, distinct, and independent units
indiscernible
Impossible or very difficult to perceive or distinguish
discernibly
In a way that can be noticed or recognized
indiscreetly
Without caution or good judgment
concerned
Worried or anxious; involved or affected