Definition · Plain-language
Types of conjunctions
English has three types of conjunctions: coordinating conjunctions join equal elements; subordinating conjunctions introduce dependent clauses; and correlative conjunctions work in pairs.
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Coordinating conjunctions: FANBOYS
The seven coordinating conjunctions — for, and, nor, but, or, yet, so — join elements of equal grammatical rank: words with words, phrases with phrases, or independent clauses with independent clauses. The mnemonic FANBOYS helps learners remember them. When joining two independent clauses, place a comma before the conjunction: "The study was large, but the dropout rate was high." When joining only two words or phrases (not full clauses), no comma is needed: "She edited and proofread the manuscript." The specific conjunction signals the logical relationship: and adds, but contrasts, or offers alternatives, nor negates both, so shows result, yet concedes, and for (formal) gives a reason. Starting a sentence with a coordinating conjunction is accepted in modern usage, though some formal style guides still discourage it.
Subordinating conjunctions
Subordinating conjunctions introduce a dependent (subordinate) clause, making it unable to stand alone as a sentence. They signal the relationship between the subordinate clause and the main clause. By cause/reason: because, since, as, now that. By time: when, while, after, before, until, as soon as, once. By condition: if, unless, provided that, as long as, in case. By contrast or concession: although, though, even though, whereas, while. By purpose or result: so that, in order that. By place: where, wherever. When the subordinate clause comes first, place a comma after it: "Although the results were promising, further trials are needed." No comma is typically used when the subordinate clause follows the main clause: "Further trials are needed although the results are promising." Note that some words — since, while — belong to more than one category depending on context.
Correlative conjunctions
Correlative conjunctions work in pairs, connecting parallel elements in a sentence. The main correlative pairs in English are: either...or (one of two options: "Either the sample was flawed or the measurement was inaccurate"); neither...nor (negating both: "Neither the sample nor the measurement was reliable"); both...and (including two: "Both the editor and the reviewer approved the revision"); not only...but also (adding emphasis: "Not only did the grant fail, but the team also lost its timeline"); whether...or (presenting alternatives: "The committee debated whether to extend or conclude the study"). The key rule for correlative conjunctions is parallel structure: the grammatical form after the first member of the pair must match the form after the second.
Key facts
At a glance
- Three types: coordinating, subordinating, correlative
- Coordinating (FANBOYS): for, and, nor, but, or, yet, so — join equal grammatical elements
- Subordinating: introduce dependent clauses; 30+ words including because, although, when, if, unless
- Correlative: paired conjunctions — either/or, neither/nor, both/and, not only/but also
- Comma rule (coordinating): comma before FANBOYS when joining two independent clauses
- Comma rule (subordinating): comma after fronted subordinate clause; usually none when it follows
- Parallel structure rule: correlative conjunctions require matching grammatical forms on each side
Common misconceptions
What people often get wrong
Often heard: Conjunctions and transitional adverbs (however, therefore) are the same thing.
Actually: Conjunctions grammatically join clauses or elements. Transitional adverbs (however, therefore, moreover, consequently) are adverbs that signal logical relationships but do not grammatically connect clauses. Using a transitional adverb with only a comma between independent clauses creates a comma splice.
Often heard: You should never start a sentence with "and", "but" or "so".
Actually: Starting a sentence with a coordinating conjunction is grammatically acceptable and is used by skilled writers for emphasis. The prohibition was a school convention designed to prevent students from writing incomplete clauses as sentences, not a rule of standard English.
Often heard: Correlative conjunctions can join grammatically mismatched elements.
Actually: Correlative conjunctions require parallel structure. Both elements in the pair must have the same grammatical form. "Either she submits the form or completing it online" is incorrect because a clause (she submits) is paired with a phrase (completing it online). Correct: "Either she submits the form or completes it online."
Common questions
FAQ
What are the three types of conjunctions?+
The three types are coordinating conjunctions (FANBOYS: for, and, nor, but, or, yet, so), which join grammatically equal elements; subordinating conjunctions (because, although, when, if, since, unless, etc.), which introduce dependent clauses; and correlative conjunctions (either/or, neither/nor, both/and, not only/but also), which work in matched pairs to connect parallel elements.
What is the difference between a coordinating and a subordinating conjunction?+
Coordinating conjunctions (FANBOYS) join elements of equal grammatical rank — two words, two phrases, or two independent clauses. Neither element depends on the other. Subordinating conjunctions introduce a dependent clause, making it unable to stand alone. The main clause remains independent; the subordinate clause leans on it for completion. The difference controls comma placement and clause structure.
What are correlative conjunctions?+
Correlative conjunctions work in pairs: either...or, neither...nor, both...and, not only...but also, whether...or. They link parallel grammatical elements and require the same grammatical structure on each side of the pair. "Not only did the grant fail, but the team also lost its timeline" illustrates the emphasis the not-only/but-also pair adds to a connected pair of ideas.
Going deeper
