To buy or sell goods to be delivered by mail(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "mail-order" in a sentence
"Female mail-order clerks at Siegel-Cooper Dry Goods Store formed the Bachelor Girls Social Club as a place where “we enjoy our independence and freedom.”"
"Brownells, the gunsmith supply mail-order firm from Montezuma, Iowa, are among the good guys in our industry, and they do more than just talk about the need to nurture the next generation of shooters."
"I only went to school through 10th grade, then finished up my diploma through a mail-order course."