A routing table has to be filled up with individual entries. The static entries stay in the routing table until they are removed or the system is switched off. The dynamic entries fed into routing tables by application protocols have their lifespan monitored and are removed after its expiration.
The English commands often use the term gateway instead of router, especially, in older manuals. The term gateway in a routing table stands for the next router (next hop) in the trip.
netstat -r command lists the contents of a routing table.
UNIX is an operating system with considerable history. The older versions of UNIX ...