spittoon (n.)

spelling conventional in 15c.-17c. English to add emphasis to borrowed French nouns ending in stressed -on; also used to represent Italian -one, Spanish -ón; all from Latin -onem. Used in rare cases to form English words, such as spittoon, octoroon.

"offspring of a quadroon and a white," 1861, an irregular formation from Latin octo "eight" (see eight) + suffix abstracted from quadroon (in which the suffix actually is -oon). So called for having one-eighth Negro blood.