At its most basic, cannabis is just a plant. One single species of flowering herb that humans have been growing for at least 8,000–10,000 years. Its official scientific name is Cannabis sativa — the same way dogs are Canis familiaris and the weed in your lawn is probably some kind of Poa. That’s it. One species.

Now, within that one species we’ve done what humans always do: we’ve selectively bred it for different jobs, the same way we turned wild wolves into Chihuahuas and Great Danes, or turned a weedy mustard plant into broccoli, cauliflower, kale, and Brussels sprouts (all the exact same species, by the way — Brassica oleracea).

So here’s the family tree in everyday terms:

• Hemp → bred for thousands of years for super-strong fiber (think ship sails and ropes), seed oil, and protein-rich seeds. Modern hemp is legally required to have 0.3 % THC or less. You could smoke a telephone pole’s worth of hemp and feel absolutely nothing besides a headache.

• Marijuana (or “weed,” “flower,” “bud,” whatever you call it) → bred to produce lots of sticky, resin-covered flowers loaded with THC, the compound that makes you feel high. Today’s good strains are usually 15–30 % THC. Same plant species, different breeding focus.

What makes cannabis unique isn’t some magical voodoo — it’s a group of natural chemicals called cannabinoids. The plant makes them in tiny glistening mushroom-shaped glands called trichomes that look like sparkly frost on the buds (those are the “crystals” people post close-up photos of). There are over 140 known cannabinoids, but the two big stars are:

• THC (delta-9-tetrahydrocannabinol) — the psychoactive one.

• CBD (cannabidiol) — the mellow, non-intoxicating one everyone puts in tinctures and gummies now.

Alongside the cannabinoids, the plant pumps out aromatic oils called terpenes — the same compounds that make lemons smell citrusy, pine trees smell like Christmas, or lavender smell relaxing. Those terpenes are why one strain smells like diesel fuel and another smells like a fruit smoothie, and they also tweak the way the high (or the medicine) feels.

Here’s the really cool part: your body already has docking stations for these molecules. It’s called the endocannabinoid system — a built-in network of receptors (mostly CB1 in the brain and nervous system, CB2 in the immune system) that helps regulate pain, mood, appetite, sleep, inflammation, and a dozen other things. Your body even makes its own cannabinoids (called endocannabinoids — anandamide is the famous one). Plant cannabinoids like THC and CBD just happen to fit those same receptors, kind of like handing your body an extra set of keys.

That’s why cannabis can do everything from spark creativity and melt anxiety for some people to ease chronic pain or stop a child’s seizures for others. It’s not “alien chemistry” — it’s chemistry our bodies already recognize.

So when someone asks, “What is cannabis?” the shortest, most accurate answer is:

It’s an ordinary plant that humans have selectively bred for millennia, and it happens to make molecules that talk directly to a regulatory system we all have in our bodies.

Same species. Different breeds. Really good at making compounds we’re wired to use.

That’s it. That’s the whole story, stripped down to the facts.