The best replacement for base is acid.

The best alternatives to base are rated as following:
★★★★★  acid
★★★  nucleophile
★★  bass
★★  acid ph
★  superstructure
★  composite reflectivity
★  alkaline
★  primer
★  access
★  based
★  nucleotide
★  salesforce
★  acid database
★  stearate
★  water base
  weak base
  plunge router
  root word of population
  water base paint
  apex of lung
  money supply
  apex of heart
  acid how to tell
  foundation
  acid foods
  acid slippery
  touch bases
  post
  face
  touch basis
  snorby
  chicken stock
  sh
  neutral
  installed base
  alkali
  bouillon
  this c#
  database
  circulation
  ip base
  plunge routers
  boat tail
  insightly
  vinyl base
  an acid
  broth
  medium base
  tris hcl
  bass music
  rav4 sport
  accent base

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

Other search terms related to base and their ratings are:
★★★★★ exponents
★★★★★ seat
★★★★★ acid
★★★★★ negative exponent
★★★★★ negative exponents
★★★★ fraction exponent
★★★★ fractional exponent
★★★ conjugate acid
★★★ getting a hit
★★ metal reaction
★★ snort
★ strong acid
★ ammonium salt
You have in mind a companion for base and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of base in all years. Click on graph for more.
base
acid
nucleophile