If I call a snake poisonous, or a frog venomous there is no knowledgeable person that will be confused about what I'm saying. The only people who bring this point up are people who love to be pedantic.
In the way that language is commonly used, yes. People have been using it wrong for so long "jealous" has effectively become synonymous with "envious". Even if I dislike and disagree with it being used this way.
If someone is eating a donut and you say "I'm so jealous [of having the donut]" I'm fairly confident most everyone would understand you mean envious by definition but are using the word jealous to convey that meaning.
Here's my comment from the last time this came up (like a week ago):
"There's been no meaning shift. The "possessive" and "envious" uses of jealous both date from the 14th century in English, and both senses were present in the ancestors of these words all the way back to Greek."
It's always been synonymous with "envious", as far back as we can trace.
Ah, but we can go even further beyond in pedantry. This distinction is only exclusive when we're talking about a living thing. When talking about the substances themselves, one is a subcategory of the other. A venomous snake is not poisonous, but a venomous venom is a poisonous poison.
This is also true. Poisonous doesn't specifically mean "dangerous when eaten" when talking about the substance. It is an insanely broad category. It basically just means the substance is harmful.
Yep, and even when talking about living things it's not a clear distinction.
In biology, poison is a substance that causes harm when an organism is exposed to it.
Venom is a poison that enters the body through a sting or bite.
In a bunch of medical fields though, poisons only apply to toxins that are ingested or absorbed through the skin and that definition sometimes carries across to zoology.
Venomous creatures are poisonous by most definitions because venom is a poison. But if the distinction is useful in a medical or zoological context then they're not.
tldr: The pedantry of eg. correcting someone who says a snake is poisonous is totally pointless and mostly wrong.