That's a fair bit trickier; there are things called dirks and things called daggers, but there is nothing 100% consistent about when either term is used. MOST dirks are single-edged and MOST daggers are double-edged, but I've seen exceptions to this, too. The closest thing I could come up with to a consistent rule would be that just about all things I've seen classified as dirks are used for piercing/stabbing, whereas daggers tend to veer towards slashing/cutting; either could be used for the opposite job, but they'd be worse at it.
However, I don't think the distinction is ever of vital importance; if you called an emergency hotline to report someone had been potentially fatally injured by a dirk or dagger, there'd be little difference in the treatment. The difference between poison and venom would be rather large, though. (Interestingly, while one could say "envenomed", the victims of poison and venom could both properly be referred to as "poisoned", which would help explain why only pedants and native English speakers would ever know, much less care, about the difference, unless they were medical personnel.)