Plastic
Plastic here means actual polymer fragments, not metaphor: tiny microplastics and nanoplastics embedded in your brain right now, found at unexpected concentrations in human neural tissue.
Plastic is a synthetic material made from long-chain polymers, widely used in manufacturing; in environmental science, it also refers to microplastics and nanoplastics—tiny polymer fragments that persist in ecosystems and have been detected in human tissues like the brain, liver, and kidneys.
What this means in real life
A child's toy made from plastic can be dropped repeatedly without breaking, unlike a ceramic cup, and costs far less to manufacture—which is why most affordable toys are plastic.
What it isn’t
Plastic is not rubber or silicone, though these materials are also synthetic polymers. Plastic specifically refers to materials that harden permanently after molding, whereas rubber remains flexible and elastic.
Commonly misused online
People often use 'plastic' as a blanket term for all synthetic polymers, or assume all plastics are equally recyclable. In reality, different plastic types (numbered 1–7) have vastly different recycling rates and environmental impacts.
Based on 2 reference sources, including NIH material. Last verified July 12, 2026.