having the property of softening or fusing when heated and of hardening and becoming rigid again when cooled; "thermoplastic materials can be remelted and cooled time after time without undergoing any appreciable chemical change"
a material that softens when heated and rehardens when cooled
a material that softens when heated and hardens again when cooled
having the property of softening or fusing when heated and of hardening and becoming rigid again when cooled
