In the OSPF Broadcast network type, routers which aren't the DR or BDR become a [...].

In an OSPF Broadcast network type, routers that are not elected as the Designated Router (DR) or the Backup Designated Router (BDR) are referred to as DROther. This terminology underscores their status in the OSPF network.

In an OSPF network, the DR is responsible for reducing the number of adjacencies formed on a broadcast network, such as Ethernet, by being the central point for exchanging routing updates. The BDR serves as a backup to the DR. All other routers in the broadcast domain that do not take on either of these roles are designated as DROther. These routers still participate in OSPF by sending and receiving routing information, but they will only communicate with the DR and BDR, rather than forming multiple adjacencies with every other router.

This specific classification helps streamline OSPF operations, preventing unnecessary overhead and promoting efficient routing protocol functioning in environments where multiple devices exist.