Polls are when organizations teach out to a percentage of the population (phone, Internet) to ask them their voting intentions.
Exit polls are the same thing, but are done after people have voted.
Sample size/distribution is supposed to be done in a way that reflects the voting intentions of the populace as a whole (doesn’t always work out that way).
I’m really hoping we’re seeing a surge of people who haven’t participated in polls but are voting for Harris. I know I’ve had pollsters reach out to me and I’ve brushed them off because of time, energy, whatever. But you can be sure as hell I got my ass out to vote