Coordinating Conjunctions

A coordinating conjunction connects two or more words, phrases, clauses, or sentences of equal importance. Examples include and, but, for, or, nor, so, yet, and conjunction pairs (known as correlative conjunctions) such as either…or and not only…but also.

In a series of three or more elements separated by commas, you need to include a coordinating conjunction before only the final item. For emphasis, however, you may choose to repeat the conjunction between every two. If you do, omit the commas from the series.

They brought a hoe, an ax, and a rake.
Jake will not stand for your jokes or taunts or insults.

And may be left out of a series to suggest that other items could be added to the list. In this case, the missing and functions like the abbreviation etc.

Star athletes need many qualities: strength, stamina, agility, focus, determination.

You may use a semicolon, but not a comma, in place of and to connect two complete sentences.

Incorrect: Jennifer met James, they went to the party together.
Correct: Jennifer met James, and they went to the party together.
Or: Jennifer met James; they went to the party together.