palinode      a poem in which the poet retracts something said in an earlier poem.
pseudoscope an optical device for producing a depth-reversed image.
cassation cancellation or reversal; a type of 18th-century instrumental suite.
tain tin foil used to silver mirrors.
librate to balance; to oscillate from side to side.
equivoque an ambiguous expression; a play on words; double meaning.
squeg (of an electronic circuit) to oscillate between zero and a certain maximum value.
diadochokinesia the (normal) ability to execute fast alternating movement.