The best replacement for gulf is bay.

The best alternatives to gulf are rated as following:
★★★★★  bay
★★★★  ocean
★★★  sea
★★★  arabian gulf
★★  atlantic
★  persian gulf
★  ocean florida
  strait
  atlantic fishing
  zetas
  atlantic coast
  atlantic warmer
  bay definition
  arab gulf
  baltazar
  arabic gulf

Your alternative for gulf is not listed? Suggest!
Speaking about gulf, one probably shouldn't forget about gulf of oman.

Other search terms related to gulf and their ratings are:
★★★★★ gulf of oman
★ oil spill
You have in mind a companion for gulf and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of gulf in all years. Click on graph for more.
gulf
bay
ocean