10 exercises — using "by definition" to ground claims in the meaning of a technical term, contrasting it with "in practice," and distinguishing it from hedges and near-synonyms.
Quick reference
By definition: a claim that is necessarily true given what a term means, not an empirical observation
Position: mobile — sentence-initial, mid-sentence (comma-set-off), or sentence-final
Contrast pair: "by definition" (spec/design truth) vs. "in practice" (real-world behavior)
Near-synonyms: inherently, necessarily, intrinsically, by its very nature
Don't confuse with: apparently/presumably (hedges), by and large (generalization with exceptions)
0 / 10 completed
1 / 10
A staff engineer explains a design constraint: "A stateless service ___ cannot retain session data between requests." Which phrase correctly signals that this follows necessarily from the meaning of the term, not from a separate observation?
By definition marks a claim as true simply because of what a word or concept means — it signals "this follows necessarily from the meaning of the term itself," not from an empirical observation. "A stateless service, by definition, cannot retain session data" — this is true by the very definition of "stateless." "By the way" introduces an unrelated aside (wrong meaning). "By and large" means "generally, with exceptions" — the opposite of a necessary truth. "By all means" grants permission ("Sure, go ahead") — completely unrelated.
2 / 10
Which sentence uses "by definition" correctly, marking a claim that is true purely by the meaning of a term?
"A singleton, by definition, has exactly one instance throughout the application" — this is correct because having exactly one instance is literally part of what the word "singleton" means; the claim is definitionally true, not an empirical fact about a specific system. The other sentences describe empirical, contingent facts (how many times something crashed, how long a deployment took, how hard a specific bug was to reproduce) — none of these are true "by definition"; they are true because of what actually happened, so "by definition" is misapplied there.
3 / 10
A code reviewer pushes back on a comment: "You said this function is idempotent, but calling it twice changes the database state — that's ___ not idempotent." Which phrase best emphasizes that the behavior directly contradicts the term's meaning?
"...that's by definition not idempotent" strengthens the claim by appealing directly to what "idempotent" means: since idempotence requires that repeated calls produce the same state, a function that changes state on a second call fails to meet the definition — no further argument is needed. "In theory" would weaken the claim by suggesting it might not hold in practice — the opposite effect. "For the record" is a discourse marker for noting something for future reference, unrelated to definitional truth. "As it were" is a hedge softening a metaphor ("so to speak") — also the wrong function here, where the point is to be maximally certain, not hedge.
4 / 10
Which position(s) can "by definition" occupy in a sentence while remaining grammatical? Consider: "[X] a race condition [Y] involves at least two threads accessing shared state [Z]."
By definition, like many sentence adverbs/disjuncts (e.g., however, in fact, essentially), is mobile: "By definition, a race condition involves..." / "A race condition, by definition, involves..." / "A race condition involves at least two threads accessing shared state, by definition." All three are grammatical and carry the same core meaning, though sentence-initial or mid-sentence placement (set off by commas) is more common and reads more naturally in technical prose than the sentence-final position, which can feel like an afterthought. Regardless of position, commas are required to set the phrase off from the rest of the sentence.
5 / 10
Which sentence pair correctly contrasts "by definition" (definitional truth) with "in practice" (empirical reality)?
"By definition, HTTP is stateless; in practice, cookies and tokens are used to simulate state..." This is the idiomatic contrastive pair: by definition states what is necessarily true given the protocol's design, while in practice pivots to how systems actually behave in real-world use, which may work around or supplement that definitional fact. This pairing is extremely common in technical writing for flagging the gap between spec and implementation. Option B wrongly claims cookies simulating state is also a definitional truth (it is not — it is an engineering workaround). Option C swaps the logic backward. Option D crams both markers onto the same clause, producing a contradictory, garbled claim.
6 / 10
A postmortem includes this line: "The retry mechanism, ___, cannot cause data loss, since every operation writes to an append-only log before acknowledging." Which phrase most precisely signals that the safety guarantee follows logically from the design, not from luck?
By definition asserts the strongest possible epistemic stance: the guarantee is not a matter of appearance, assumption, or claim — it follows necessarily from the append-only-log design being described. "Apparently" and "presumably" both hedge the claim, suggesting it seems true or is assumed true but isn't verified — the opposite of the certainty intended. "Allegedly" implies the claim is disputed or unverified, often used skeptically — entirely wrong tone for a postmortem stating an engineering guarantee.
7 / 10
Which sentence misuses "by definition" by attaching it to a claim that is actually just common or typical, not logically necessary?
"Most production outages, by definition, happen on a Friday afternoon" misuses the phrase: this is a joke about observed frequency (an empirical, statistical pattern — or a superstition), not a truth that follows from the meaning of "outage." The correct connector for that idea would be something like "it seems" or "anecdotally." The other three sentences are genuine definitional truths: purity entails no side effects, immutability entails no post-creation modification, and a null pointer dereference is defined as accessing a reference to no object — all follow necessarily from the terms themselves.
8 / 10
Choose the best synonym for "by definition" in this sentence: "A deadlock, ___, requires a cycle of processes each waiting on a resource held by another."
Inherently is the closest synonym here — both signal that a property is built into the very nature of the thing being described, not incidental to it. "A deadlock inherently requires a cycle of processes..." carries nearly the same force as "by definition." "Occasionally" (frequency), "seemingly" (appearance, hedge), and "coincidentally" (chance) all describe contingent, non-necessary relationships — the opposite of what "by definition" and "inherently" both express. Other near-synonyms worth knowing: necessarily, intrinsically, by its very nature.
9 / 10
Which sentence correctly uses "by definition" to preempt an objection in an architecture discussion?
"...a facade pattern, by definition, wraps multiple subsystems behind one interface — that's the whole point" correctly uses the phrase to preempt an objection: it shows the apparent "violation" is actually inherent to what a facade pattern is, so the criticism misapplies the pattern's intended purpose. Option B pairs "by definition" with an unrelated claim about a decision not yet made — no definitional content at all. Option C hedges with "might," which contradicts the certainty "by definition" is supposed to convey — a definitional truth cannot be merely possible. Option D uses "by definition" to introduce a recommendation ("we should"), which is a judgment, not a necessary truth — the wrong grammatical/logical role entirely.
10 / 10
Which explanation best distinguishes "by definition" from "technically" in engineering discussions?
"By definition" grounds a claim in the accepted meaning of a term and is usually offered constructively, to clarify. "Technically" often has a slightly different, more pedantic flavor — it frequently introduces a narrow, literal reading that undercuts or complicates a broader claim someone just made ("Technically, the SLA doesn't cover this edge case, even though it's clearly in the spirit of the agreement"). They can overlap, but "technically" carries a stronger implication of "strictly speaking, contrary to what you might assume," while "by definition" more neutrally states a necessary truth. Neither is restricted to a single field, and "technically" is not more formal — if anything, it is the more conversational of the two.