Suspended chords are chords, no...they're a single note playing outside like a kid playing stickball in the street after all the other kids have resolved to going safely home to eat with they're mothers, these defiant notes linger outside, they'll come in soon.
listen to Bach and hear chords but also, and more dramatically, hear each melody line rallying towards tension and receeding into resolution...the kids playing stickball and then running inside after mother calls them, "you crazy kids, get in here for dinner or i'm gonna kick your asses."
Most of the chord's tones answer, "ok, mom. we're coming." when they get inside, when they get home, when they're resolved, when they're part of the I chord or some other stable structure and when one of them is left in the street, being defiant, lingering, causing tension, "Where the fuck is JOHNNY!" you've got a suspension, suspended chord, call it what you like.
Suspension is when the other melodies have all settled on resolution and one crazy fucker's still out there wallowing in tension world...everyone knows he's coming in to eat with the family but it's this delay which we call suspension and from here, we'll see what we mean by suspended chords.
They are movement chords. In common usage, in guitar player and crap like it, there are Gsus4, Dsus2 and etc.
But in the real world, the world of sound, there's tension, movement, and resolution. Think of suspended chords being in the tension family...but they're also in the resolution family.
To really understand how to use suspended chords, and understand what's useable about them, we have to change our thinking a bit and get away from 'what chords' we're playing and look inside the chords and see what each of the notes are doing.
this isn#t complete...i'm working on completeing this page...
For any answer about any of this stuff consult Bach or his kids.
In 'classical' music, a term over applied to orchestral music, there are four or five common suspensions.
The 9-8 suspension:
the 6-5 suspension
and 4-3: Try going from a G7 (tension) to C but let the F note linger around into the C chord (resolution) world