What "reachability" means in a routing table?

Check this routing table

track 1 ip route 10.46.52.5 255.255.255.255 reachability
ip route 10.1.0.0 255.255.128.0 10.243.222.1 track 1
ip route 10.1.128.0 255.255.128.0 10.243.222.1 track 1
ip route 0.0.0.0 0.0.0.0 10.11.70.2 name FW_INTERNET
ip route 10.1.3.211 255.255.255.255 GigabitEthernet0/0.10 tag 20
ip route 10.1.5.1 255.255.255.255 GigabitEthernet0/0.10 tag 20

In the first route what does reachability mean?

Solution 1:

it just checking connectivity...

Solution 2:

reachability is not part of the routing table, but of an object tracking instruction. It checks whether the route is reachable (see here).