The best replacement for sign on is sign in.

The best alternatives to sign on are rated as following:
★★★★★  sign in
★★★★  ldap
★★★  federated identity
★★★  oauth
★★★  active directory
★★★  identity management
★★  pass through authentication
★  sign-on
  secure store service

Your alternative for sign on is not listed? Suggest!
Speaking about sign on, one probably shouldn't forget about pen in your hand.

Other search terms related to sign on and their ratings are:
★★★★★ pen in your hand
You have in mind a companion for sign on and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sign on in all years. Click on graph for more.
sign on
sign in
ldap