The gallows. (Latin, furca.) Cicero (de Divinitate, i. 26) says, “Ferens furcam ductus est, ” often quoted in proof that criminals condemned to the cross were obliged to carry their own cross to the place of execution. But the ordinary meaning of furca is a kind of yoke to which the hands of criminals were fastened. The punishment was of three degrees of severity: (1) The furca ignominiosa; (2) the furca pænalis; and (3) the furca capitalis. The first was for slight offences, and consisted in carrying the furca on the shoulders, more or less weighted. The second consisted in carrying the furca and being scourged. The third was being scourged to death. The word furcifer meant what we call a gallows-bad or vile fellow.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894