One 360° turn in a spring or similar helix.
A mathematical operation on two functions that produces a third that expresses how the shape of one is modified by the other; the integral of the product of the two functions after one is reflected about the y-axis and shifted along the x-axis.
The shape of something rotating; a vortex.
Any of the folds on the surface of the brain.
A twist or fold.
The state or condition of being convoluted.
A function which maps a tuple of sequences into a sequence of tuples.
A wave having a white crest; a breaker
Any of several birds having a white patch on the head
A member of a self-appointed vigilante committee that carried out lynchings. Some early ones wore white hoods or masks.