The best replacement for core is periphery.

The best alternatives to core are rated as following:
★★★★★  periphery
★★★★  cpu
★★★★  headline inflation
★★★★  context
★★★  core 2 duo
★★★  thread
★★  corps
★★  quad core
★★  pentium
★★  spike aerator
★  single core
★  dual core
★  abs
★  premium
★  processor
★  socket
★  xeon
★  i7
★  dual processor
★  intel dual core
★  elective
★  i3
★  core 2
★  core duo
  intel pentium
  non core
  intel
  logical processor
  core plus
  s duos 2
  nexus
  prepreg
  pentium processor
  core knowledge
  quad core processor
  quad core processors
  amd
  quattro
  star testing
  duo core
  i5
  state standards
  pentium 4
  hyper threading
  xperia m
  flex
  hyperthreading
  cavity
  headline cpi
  thermostat

Your alternative for core is not listed? Suggest!
Speaking about core, one probably shouldn't forget about hdmi.

Other search terms related to core and their ratings are:
★★★★★ hdmi
★★ curriculum
★ attunement
You have in mind a companion for core and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of core in all years. Click on graph for more.
core
periphery
cpu