It generally refers to any non-Z06 or non-convertible or non-"special edition" (50th Anniversay, Indy Pace Car, etc) car. IOW, it's generally going to be a relatively unoptioned Coupe which is by far, the most popular/common model.
I have a base coupe, hud, mem package, heated mirrors that also dim, high polish alum wheels, f45 shocks ride control, 12 disk changer, power seats driver and pass., tilt and tele steering wheel, ac/ cruise control...So my car is loaded with all kinds of options.Although I have FE1 suspension and thats base for sure...best base model car I've owned
[SIGPIC][/SIGPIC] 2002 Black Coupe
LS1 A4 2:73
Fixes: Headlight gears,Passenger door lock relay, Multifunction lever and EBCM relay fix
Sac City Fangs, Sequential Tails, Hankook V12 EVO,C6 Z06 shocks
Callaway Honker, Billy Boat PRT/Speedway Tips Save the wave!
It typically means a car without any optional equipment.
When you see it in a vette advert it most likely refers to a coupe (even with optional equipment). Mine is a 3LT optioned coupe but if the add was written by a non vette aware person they would say it was the "base" corvette.
My 02 came with Hud, polished wheels dual zone climate etc. etc, but I consider it base because it has the base, non Z51 suspension and 2:73 rear end instead of 3:15 performance axle (for automatics). I equate base with base suspension, not so much with other goodies. All my initial mods were about suspension improvements - still haven't changed the rear end, but considering it.