What Is a Conjunction?

Your teacher says "don't start a sentence with and," someone else says a conjunction is a "joining word," and you're left nodding along without ever being shown what one actually is. It's one of those grammar words that gets used around you far more often than it gets explained. And the funny thing is, you've been using conjunctions all day without a second thought — in the playground, at the dinner table, in every text you send.

Here's the reassuring bit. Every time you say "fish and chips," "tired but happy," or "I stayed in because it was raining," you're using a conjunction — and using it correctly. You already know how they work, deep down; your ear reaches for the right joining word automatically. This article isn't going to teach you a brand-new skill. It's just going to give these little words a name and sort them into their small, tidy families, so that when a question asks you to find the conjunction, you know exactly what you're looking for.

Where we're heading. By the end you'll be able to:

• Say what a conjunction does.
• Use the everyday joiners — and, but, or, so, because.
• Tell the difference between joining two equal ideas and hooking a smaller idea onto a bigger one.

Beginner: what a conjunction does

A conjunction is a word that joins things — words, groups of words, or whole ideas — so you don't have to write everything in tiny separate sentences.

Watch what happens without them:

I like football. I like art. I don't like homework.

Choppy, isn't it? It reads like a robot listing facts. Conjunctions smooth it out:

I like football and art, but I don't like homework.

Same facts, one sentence, and it actually sounds like a real person talking. The little words and and but did all the joining, and they also did something cleverer: but quietly signals that a contrast is coming, so your reader is ready for the change of direction. That's a conjunction earning its keep.

The everyday joiners are worth knowing by heart: and (adds), but (contrasts), or (gives a choice), so (shows a result), because (gives a reason). Five small words, and between them they do an enormous amount of the joining in everything you write.

Common Mistake: thinking a conjunction is just any small word. The, a, in, on are small too — but they don't join two ideas, so they aren't conjunctions.

Quick recap:

• A conjunction joins words, groups of words, or whole ideas.
• The everyday ones: and, but, or, so, because.
• They stop your writing sounding choppy.

Intermediate: two ways of joining

Conjunctions join in two main ways, and it's worth being able to feel the difference.

Joining two equal ideas — this is what and, but, or, so do. Both halves could stand on their own as sentences, and the conjunction sits neatly between them, treating them as equals:

The bell rang, so we packed our bags. I could take the bus, or I could walk.

The full set of these "equal joiners" (grammar books call them coordinating conjunctions) gets its own article — the FANBOYS words.

Hooking a smaller idea onto a bigger one — this is what because, when, if, although do. One half is the main idea; the other leans on it and can't stand alone:

We went inside because it started raining.

"Because it started raining" isn't a sentence by itself — it needs the main part to make sense. These "leaning joiners" are the subordinating conjunctions, and they have their own article too.

Common Mistake: leaving a "leaning" half on its own. "Because it started raining." isn't a full sentence — your reader waits for the rest. Finish the thought: "We went inside because it started raining."

A step further: pairs, and words that only look like joiners

Two more things are worth knowing once the basics feel steady.

First, some conjunctions come in matching pairs that work together across a sentence: either… or, neither… nor, both… and, not only… but also. Grammar calls these correlative conjunctions, but you don't need the label to use them — you can either walk or take the bus, neither the cat nor the dog would come in. The trick is to keep both halves balanced: if either is followed by a doing-word, or should be too. They come up again in the FANBOYS article, so you'll meet them properly there.

Second, watch out for words that look like joiners but behave differently — words like however, therefore and meanwhile. They feel as if they should join two sentences the way but or so do, but they don't work the same way with punctuation. "It was raining, however we went out" isn't quite right; these words usually need a full stop or a semicolon in front of them, not just a comma. They're properly called conjunctive adverbs, and because they're such a common trap, they have their own article. For now, just know that not everything that feels like a joiner counts as a true conjunction.

Why it matters

Conjunctions are the difference between writing that sounds like a young child listing things and writing that flows like a thinking person. As you move up through school, teachers want longer, connected sentences that show how your ideas relate — that one thing caused another, that two facts sit in contrast. Every one of those relationships is carried by a conjunction. Choosing the right one — because for a reason, but for a contrast, although to admit something before disagreeing — makes your writing clearer and more grown-up. These small words punch well above their weight.

Quick check

1. Circle the conjunction: We waited inside until the rain stopped.

2. Join these with one conjunction: It was late. We went home.

3. Which of these can stand alone as a sentence — "and my brother" or "my brother laughed"?

4. Is because joining two equal ideas, or hooking a smaller idea onto a bigger one?

5. Complete the pair: You can have ___ the red one ___ the blue one.

6. Which word is a "joiner-that-isn't-quite" needing stronger punctuation — and or however?

Where next

• Coordinating & Correlative Conjunctions (FANBOYS) — the equal-joiners, and the pairs like either…or.
• Subordinating Conjunctions — the leaning-joiners: because, although, when, if.
• Conjunctive Adverbs vs Conjunctions — words like however that look like joiners but punctuate differently.
• → The Parts of Speech — where conjunctions sit among the eight word classes.