Hello,
I'll take a stab.
Assuming we are talking about physical assets ("physical" in this context means "you can touch it"):
DPC - Dense Port Concentrator, ICHIP-based Ethernet line card for MX240/480/960 or Services card (called MS-DPC) for MX240/480/960
FPC - Flexible PIC Concentrator, line card for M/T-series/MX240/480/960. Can have interface (sub)cards (also called PICs) inserted in it.
MPC - Modular Port Concentrator, Trio chipset-based line card for MX240/480/960. Can have interface cards (also called MICs) inserted in it.
PIM - Physical Interface Module, interface card for J-series and SRX-series boxes
PIC - physical Interface Card, interface card for M/T-series/MX240/480/960 boxes
MIC - modular Interface Card, interface card for MX5/10/40/80/240/480/960.
HTH
Thanks
Alex