1. An imaginary line or standard by which things are measured or compared
   "they established a baseline for the budget"
    
2. The back line bounding each end of a tennis or handball court; when serving the server must not step over this line
   "The player's foot touched the baseline, resulting in a fault";
   - service line
    
3. The lines a baseball player must follow while running the bases
   "He barely touched the baseline as he rounded second base"

Derived forms: baselines

Type of: criterion, line, measure, standard, touchstone

Encyclopedia: Baseline