A subordinating conjunction is a word that joins a dependent clause to an independent clause, creating a complex sentence. It signals that one idea depends on another for full meaning. Common examples include because, although, since, unless, and while.
These words introduce clauses that cannot stand alone. For instance, "Because it was raining" is incomplete without a main clause like "we stayed inside." The subordinating conjunction "because" shows the relationship between the two ideas-causation in this case.
According to the Purdue Online Writing Lab (OWL), subordinating conjunctions are essential for expressing detailed relationships such as cause, contrast, condition, and time. They allow writers to build layered logic in prose and avoid choppy, repetitive sentence structures.
When a subordinating conjunction appears at the beginning of a sentence, it introduces a dependent clause. That clause relies on the independent clause to complete the thought. The dependent clause cannot function alone.
For example: "Although she studied hard, she failed the test." Here, "although" marks the start of a contrastive dependent clause. The sentence's meaning hinges on the connection between effort and outcome. Removing "although" changes the structure entirely-it would then read "She studied hard, she failed the test," which lacks proper coordination.
Subordinating conjunctions can also appear mid-sentence. In "He left early because the meeting ended late," "because" connects the reason (dependent clause) to the action (independent clause). The placement affects emphasis: moving "because" to the front shifts focus to the cause.
Subordinating conjunctions fall into categories based on the logical relationship they express. Each category serves a distinct purpose in sentence construction.
| Type | Function | Examples |
|---|---|---|
| Cause/Effect | Shows why something happened | because, since, as, because |
| Contrast | Highlights opposition or difference | although, though, even though, while |
| Condition | States a requirement or hypothetical situation | if, unless, provided that, as long as |
| Time | Indicates when an event occurs | when, while, after, before, until |
| Place | Specifies location | where, wherever |
Each type shapes how readers interpret the sequence and significance of events. For example, "After the storm passed, we resumed our hike" uses "after" to establish temporal order. Without it, the sentence loses clarity about timing.
Some conjunctions carry subtle differences. "Although" and "though" are interchangeable in most contexts, but "although" is slightly more formal. "While" can indicate contrast ("While he slept, she read") or simultaneous action ("While she cooked, he set the table"), depending on context.
Subordinating conjunctions appear in academic writing, legal documents, technical reports, and everyday conversation. They enable precision in expressing relationships between ideas.
In research papers, "because" clarifies causality: "The results were inconclusive because the sample size was too small." This avoids vague phrasing like "the results were bad," which lacks explanation.
Another common error involves comma usage. A comma follows a subordinating conjunction when it begins a sentence. "Because the bus was late, we missed the show." But no comma is needed when the main clause comes first: "We missed the show because the bus was late."
Subordinating conjunctions are frequently mistaken for coordinating conjunctions (FANBOYS: for, and, nor, but, or, yet, so). Coordinating conjunctions join equal parts-two independent clauses. Subordinating conjunctions link unequal parts: a dependent clause to an independent one.
Consider: "I wanted to go, but it was raining." Here, "but" connects two independent clauses. Now compare: "I wanted to go, but it was raining." The second sentence is incorrect because "but" doesn't introduce a dependent clause. "But" cannot begin a sentence with a dependent clause unless it's part of a compound sentence.
Also, subordinating conjunctions differ from conjunctive adverbs like "however," "therefore," and "." These modify entire clauses and require a semicolon or period before them. "She failed the test; however, she passed the final exam." "However" is not a subordinating conjunction-it's a transitional adverb.
Take this sentence: "Unless you submit your application by Friday, it will not be reviewed."
"Unless" is a subordinating conjunction introducing a conditional clause. The dependent clause is "you submit your application by Friday." The independent clause is "it will not be reviewed."
The sentence expresses a clear consequence. Without "unless," the sentence would lack the conditional structure. Replacing it with "if" changes nuance: "If you submit your application by Friday, it will be reviewed" implies a positive outcome upon submission. "Unless" emphasizes exclusion: failure to act leads to inaction.
This distinction matters in formal writing. Legal contracts, policy statements, and academic arguments rely on precise logical connectors. Misusing "unless" for "if" alters the meaning of obligations and deadlines.
I once edited a student essay where "because" was misused to start multiple sentences. The original draft read: "Because the weather was cold. Because the roads were icy. Because the school closed." Each sentence began with "because," making the writing feel repetitive and unstructured. I revised it to: "The school closed because the weather was cold and the roads were icy." This version uses a single subordinating conjunction to link causes, improving flow and conciseness.
Understanding the difference prevents structural errors. Subordinating conjunctions create hierarchical relationships. Coordinating conjunctions create balanced ones.
Compare:
Only the first sentence correctly uses a subordinating conjunction. The second uses a coordinating conjunction. Mixing them leads to awkward or ambiguous constructions.
The subordinating conjunction definition centers on function: linking dependent and independent clauses to clarify logic, time, cause, or condition. Mastering them improves clarity, coherence, and precision in written communication.