Definition of arachnodactyly in US English:

arachnodactyly

noun

Medicine
  • The condition of having unusually long and slender fingers and hands (and often toes and feet), associated especially with Marfan's syndrome and similar connective tissue disorders.

Origin

1920s; earliest use found in Journal Orthopaedic Surgery. From ancient Greek ἀράχνη spider + -o- + -dactyly, after French arachnodactylie.