What exactly are range locks?

Serializable This is the most severe level of isolation. Serializability in a lock-based concurrency control DBMS solution necessitates the release of reading and write locks (acquired on specified data) at the conclusion of the transaction.
Well, the topic introduces Isolation in Wikipedia and Scaler. Range locks must also be obtained when a SELECT query has a ranged WHERE clause, particularly to avoid the phantom reads phenomena (see below). No locks are acquired while utilizing non-lock-based concurrency management; yet, if the system detects a write collision among numerous concurrent transactions, only one of them is permitted to commit. For additional information on this issue, see snapshot isolation.
However, the entire text did not describe "range-locks," and Google also did not provide an appropriate definition.
What are "range-locks," and how do they differ from "read lock" and "write lock"?