I play Minecraft on my PC, but my son wants a laptop. Can he join me in my world? Can PC's/laptop's play together? We both play together on MCPE, but I prefer PC.
Assuming you are both playing the same version of Minecraft, Yes.
You will both need separate accounts, as the same MC account (UUID) cannot be in the same world twice. However, you will both need to play the same type of Minecraft as well as have the same version. For example if one of you is playing the Windows 10 Edition and the other the Java version, you won't be able to play together.
This answer has information on how to connect.
It's as easy as connecting to another player's world in Minecraft PE. One player opens the game to the local network ("LAN") through the ESC menu, the other one connects through the multiplayer list. This is possible because Minecraft for PC and laptop is the same thing.
If you would have any issues, check out this: Why isn't my Minecraft LAN server working?
While the other answers aren't wrong, I believe they answer the wrong question. If I understand this correctly, your issue is with knowing whether or not a desktop user can play with a laptop user. Most likely the question comes from the fact that Minecraft has an Xbox version that isn't compatible with desktops.
With that taken care of, yes, it is possible to play on a laptop with desktop players. That is because the computer versions of the game are all compatible with one another (All operating Systems can play with one another).
In sum, yes it's possible to play desktop/desktop , desktop/laptop and laptop/laptop, even if they have different operating Systems (Windows, Mac, Linux, etc..)
As others have stated, as long as you both are running the same version, you can connect to the same server.
The term PC originally meant PC Compatible, as in IBM PC. As opposed to Apple Macintosh. WhatIs.com.......I still have some disks laying around that say PC-compatible somewhere
Then it got changed to something that made more sense, Personal Computer, which makes more sense now, seeing as everything can more or less be made to play nice across OS's.
And now it has been co-opted yet again, by who knows what entity, who wants to state that a PC is a system that sits motionless, while a laptop has no classification.....which makes no sense......
Laptops and towers/desktops, are both PCs.