Can someone please expound this joke?
What's the definition of counterpoint? Two guitarists sight reading the same score.
I quote a comment from these Reddit threads, but not this r/ELI5 one as there`re enough quotes.
Counterpoint is basically having more than one melody at once. It's not usually associated with popular music (which is why people often point it out when it is there) but it's not absolutely unheard of either[.]
Counterpoint means "point against point".
In its basic form, you have two melodies playing at the same time. Harmony is created by each pair of notes that you hear at any given moment, and it's constantly changing as each voice moves. The rules of counterpoint help define what does and doesn't sound good in this system. When we analyze counterpoint, we're looking at the intervals created by each pair of notes, and how they're related to their neighbors.
Contrast this with "modern" chord-based music. The simplified form of this is that you play a chord (a group of intervals) for a measure while the melody dances around independently. Then you do another chord and the melody moves around some more.
In counterpoint there's no chords, just two melodies that need to sound good together.
Simply put, counterpoint is a method of writing multiple melodies that are sufficiently distinct to be heard at once. Common counterpoint rules include avoiding parallel fifths and octaves (makes it difficult to distinguish the lines), avoiding crossing the lines (same reason), avoiding large leaps (breaks the continuity) and others. There are multiple alternative theories that have developed in more recent times, but the majority of contrapuntal music that you will encounter will obey the rules that I've described.