Denormalization
In plain terms
Intentionally duplicating data to speed up reads.
Going deeper
Denormalization adds redundancy to avoid expensive joins, trading storage and write complexity for faster reads. It's the opposite of normalization.
Under the hood
Common in NoSQL and read-heavy systems; you must keep duplicates consistent on writes.
Examples
NoSQL data modeling, read-optimized tables, caching computed values, analytics.
Think of it like...
Like keeping a copy of a frequently-needed phone number in several places for quick access.