Question
In the context of databases, Is a B-tree the same as an index?
Answer
For many intents and purposes they are the same.
"B-Tree is a self-balancing search tree." Taken from
https://www.geeksforgeeks.org/introduction-of-b-tree-2/
"B-tree is a data structure that store data in its node in sorted order."
https://dzone.com/articles/database-btree-indexing-in-sqlite
This source says that the "B" stands for "balanced" (not "binary"): https://use-the-index-luke.com/sql/anatomy/the-tree
To learn more see this: https://www.geeksforgeeks.org/difference-between-binary-tree-and-b-tree/