A length of lumber that is 4 inches thick and 4 inches wide, or that is trimmed to slightly smaller dimensions.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "four-by-four" in a sentence
"✒Thanks to WWD Media in the US for pointing out that Condé Nast Traveler has hot news for posh voyagers in the American version's April issue: Libya is one of its "15 best places to see right now" the Roman ruins are nice, it seems, as is traversing the Sahara "by four-by-four or camel"."
"If the wrong people had seen the four-by-four—if the wrong people knew an American officer was eating dinner here, along with two spooks, a tribal sheikh, and a couple of interlopers, then this would be the moment to attack."
"That is how Mohamad and I ended up in the back of a four-by-four with Alan and a Philadelphia judge named Daniel L. Rubini, roaring down the middle of Palestine Street in a two-car convoy that was painfully, conspicuously, deafeningly American."