A small furrow, ridge or crease in an otherwise smooth surface.
A line or crease in the skin, especially when caused by age or fatigue.
Spending time out in the sun may cause you to develop wrinkles sooner.
A fault, imperfection or bug especially in a new system or product; typically, they will need to be ironed out.
Three months later, we're still discovering new wrinkles.
A twist on something existing; a novel difference.
A winkle