"Conjunction Junction, what's your function? Hooking up words and phrases and clauses." These lyrics from Schoolhouse Rock sum it up: a conjunction is all about joining things together.
The words and, but, and or are conjunctions, linking words and phrases together to form sentences. Other kinds of conjunctions bring groups together, such as organizations working in conjunction to present a big event; or bring objects together, like a conjunction in a house's plumbing system where pipes meet. Conjunction could also mean things happening at the same time, such as free Schoolhouse Rock screenings that are presented in conjunction with a National Grammar Day celebration.