Moore v. United States: Income must be realized

A key issue in Moore v. United States is whether income has to be realized to be taxable.  An amicus brief in the case was filed by Professors of linguistics who did a 1913 search of the use of the words "income" and "derived" from the Sixteenth Amendment and found that overwhelmingly Americans thought income has to be realized to be taxable.  The online dictionary of etymology concurs as follows:

Online Etymological Dictionary:

income (n.)

1600. 1300, "entrance, arrival," literally "a coming in;" see in(adv.) + come(v.). Perhaps a noun use of the late Old English verb incuman "come in, enter." Meaning "money made through business or labor" (i.e., "that which 'comes in' as payment for work or business") first recorded c. 1600. Compare German einkommen "income," Swedish inkomst. Income tax is from 1790, introduced in Britain during the Napoleonic wars, re-introduced 1842; in U.S. levied by the federal government 1861-72, authorized on a national level in 1913.

also from c. 1300

The United States should lose this case.  Income literally has to "come in" before it is taxable both as the word was used in 1913 and based on its etymology.