What does fretless base mean?

A fretless bass is a type of Bass Guitar that lacks the metal frets typically found on standard basses. This design allows for a smoother, continuous fingerboard, enabling players to produce glissandos and microtonal variations in pitch. It requires more precise finger placement for accurate notes, making it popular in genres that emphasize expressive playing, like jazz or certain styles of rock. Fretless basses often have a warmer, more rounded tone compared to their fretted counterparts.