1. plural of preformation; the act or process of forming beforehand
Usage: formal; technical
2. in biology, structures or patterns that exist in embryonic form before full development
Usage: biological; developmental biology

Examples

• The scientist studied the preformations visible in the early embryo.
• These preformations would later develop into complex organ systems.
• The theory of preformations was popular in early developmental biology.
• Researchers observed distinct preformations in the tissue samples.
• The preformations indicated the future structure of the organism.
• Modern biology has moved beyond simple preformation theories.