From what I understand arduino is a programmable control module with rewritable ss memory. What do you call the family of ics that are used in common day electronics from your average calculator to a tomagachi game?
I call those COBs. Chip On Board. Typically they are a custom die which is mounted direct on the PCB then covered in black epoxy (or whatever that black stuff is). There is absolutely nothing "generic" about them - each one is custom designed and manufactured in their hundreds of thousands (or millions) for the one specific bulk job.
The chip fabricator may build the design up out of various modular blocks, but the resultant chip is custom and cannot really be used for anything else.