# thermoplastic

/ˌθɝməˈpɫæstɪk/ (US) · /θˌɜːməplˈɑːstɪk/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/thermoplastic
Updated: 2026-10-18

## Definition

a type of plastic that becomes soft when you heat it and hard again when it cools, so you can reshape it many times.

For teachers: a polymer material that softens on heating and hardens on cooling, allowing repeated reshaping without chemical change. Frequently contrasted with thermosetting polymers, which harden permanently after first heating.

## Examples

- This bottle uses thermoplastic that softens in heat.
- The factory melts thermoplastic pellets and injects them into moulds to make phone cases.
- Unlike thermosetting resins, thermoplastic can be reheated and remoulded many times, which makes recycling easier though repeated heating may gradually weaken the material.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.