Conjunctions are words that join other words, phrases, or clauses. In English, the most common type for basic connections is the coordinating conjunction. Coordinating conjunctions link elements of the same type, such as two nouns or two clauses. They do not change the word order in simple sentences. They help create longer sentences without changing the basic sentence structure.

'And' adds information by joining two or more elements. It connects items of equal importance, such as two subjects or two predicates. When 'and' connects clauses, both clauses remain independent if each has a subject and a verb. In lists, 'and' usually comes before the final item. 'And' does not express contrast or choice.

Word/Phrase	Definition
and	'And' joins elements to add information or continue an idea.
tea and coffee	A choice or pair presented together as both included.
He ran and she sang	Two actions connected as both happening or both being stated.

'But' connects elements by showing contrast or an exception. It joins two ideas where the second idea limits, opposes, or qualifies the first. When 'but' connects two clauses, both are usually complete thoughts. 'But' often signals a change or a difference in expectation. 'But' does not indicate alternatives or options.

Word/Phrase	Definition
but	'But' joins elements to show contrast or an unexpected result.
He is tired but happy	Two states connected with a contrast between them.
I called but no one answered	An action paired with an outcome that contrasts with expectation.

'Or' connects elements by presenting alternatives or choices. It links words or phrases when only one option is selected or when options are being listed. In questions, 'or' offers possible answers or paths. When 'or' connects clauses, it suggests different possible results. 'Or' does not inherently add or contrast; it frames selection.

Word/Phrase	Definition
or	'Or' joins elements to offer alternatives or options.
Tea or coffee	A choice between two items, with selection implied.
Hurry or you will be late	Two possible outcomes connected as alternatives.

Coordinating conjunctions are used in lists to join the final item. In a list of three or more items, a comma may appear before 'and' or 'or'; this is called the serial comma. The basic rule is that the conjunction joins the last two items, not every item in the list. In short lists, no comma is needed when only two items are joined. The structure remains parallel when each item in the list matches in form.

Rule
Use 'and' or 'or' to join the last two items in a list.
A serial comma before 'and' or 'or' is optional in English and depends on style.
Keep list items parallel in form when using a conjunction.

Coordinating conjunctions join two independent clauses to form a compound sentence. Each clause has its own subject and verb and can stand alone as a sentence. In writing, a comma is typically placed before the conjunction when joining two full clauses. Without a conjunction, joining clauses with just a comma creates an error called a comma splice. The conjunction maintains the connection without changing the basic word order of each clause.

Rule
Use a comma before a coordinating conjunction when joining two independent clauses.
Each side of the conjunction should be an independent clause if you use the comma.
Do not join two independent clauses with a comma alone.

'And,' 'but,' and 'or' are coordinating conjunctions that connect words, phrases, and clauses of equal value. 'And' adds information, 'but' shows contrast, and 'or' offers alternatives. Lists use a conjunction to join the final item, with optional use of the serial comma based on style. Coordinating conjunctions can join independent clauses, usually with a comma in writing. These patterns allow clear and efficient connections in English sentences.