The term softail refers to motorcycles an bicycles that feature a moveable rear suspension system with springs or shock absorbers to absorb bumps. On motorcycles, the shock absorbers or springs are hidden underneath out of view to give the appearance of a hard-tail or rigid frame. The word softail is a registered trademark of Harley-Davidson motorcycles coined with the release of the FXST Softail in 1984. Since then, the word has expanded to include other motorcycles with hidden rear suspensions as well as bicycles incorporating a rear suspension.