B Tree
In plain terms
A balanced tree with many children per node, optimized for disk.
Going deeper
B-trees keep data sorted with high branching factor, minimizing disk reads by storing many keys per node. They're the backbone of databases and file systems.
Under the hood
Wide nodes match disk-block sizes, reducing I/O; the B+ tree variant keeps all data in leaves for efficient range scans.
Examples
Database indexes, file systems (NTFS, ext4), PostgreSQL/MySQL indexes.
Think of it like...
Like a filing cabinet with broad, shallow drawers so you reach any file in very few pulls.