Home audio and HT are comprised of two, three or four basic components.
A pre amplifier handles source selection, tone controls and virtually all the buttons and knobs you can twist, push and flip. there's a little amplification going on here but not enough to drive loudspeakers.
A power (or main) amplifier takes the output of the preamp and "amplifies" but not enough to drive loudspeakers.
These are available separately but are available on one chassis. That' called an "integrated amplifier.
Throw a tuner on the same chassis as the integrated amplifier and you have a stereo receiver.
How, for HT, there's another wrinkle.
A Processor takes a signal and "decodes" from it up to seven different channels and provides control over the subwoofer. I don't think I've ever seen one as a standalone unit. I can only recall ever seeing these integrated with a preamp, since there are control functions on these and the two are a perfect match. That, plus their roles are greatly entwined.
A HT receiver combines all these functions plus amplifiers for all the channels. except a subwoofer.
IMNSHO, If all you want, and will ever want, is two channels, then a two channels receiver or integrated amp is the way to go. Trying to integrate a stereo integrated or receiver into a full blown HT system requires many compromises and operation can become a bit complex. I would recommend you stick to a HT receiver (or a pre/pro and all the accompanying hardware) if you are even thinking about multi-channel