- carbon monoxide gas
- atomic number 27
- conscientious objector
(neologism, nonstandard) They (singular). Gender-neutral subject pronoun, coordinate with gendered pronouns he and she.
(neologism, nonstandard) Them (singular). Gender-neutral object pronoun, coordinate with gendered pronouns him and her.
Origin of Co
var of com-, orig. occurring only before a vowel, h, or gn
From Webster's New World College Dictionary, 5th Edition
Middle English from Latin variant of com- com-
From American Heritage Dictionary of the English Language, 5th Edition