Not to be a douchenozzle but venomous would be the correct word. Venom must be injected while poison must by ingested. Sorry, I was wanting to be a Herpetologist and no, that isn't the study of an STD, lolz. ;)
There are four species of venomous snakes, whose toxin is harmful to humans(there are two others but whose venom is nontoxic to humans and most animals), and native to TN; Copperhead, Western Water Moccasin, Pigmy Rattlesnake, and Timber Rattlesnake. Copperheads generally about 50% of the time give a dry bite but the younger the copperhead the more likely you are to get dosed with venom but NOT because they have more venom(urban myth) but because the ADULTS are more aware of their venom control and are only biting out of self-preservation. Water Moccasins are only indigenous to West TN hence their name and most sightings east of West TN are 99% chance to be a water snake as the two are close cousins and look VERY similar to the point to where they can only be told apart from the distingushing features of the head, namely the eyes as the Common Watersnake will have circular shaped eyes and the ol' Cottonmouth will have eliptical eyes much like a cat not that you wanna be that close, lol. Also, you can't distinguish the Water Moccasin from its "white mouth" as ALL snakes indigenous to TN have white mouths.