Term Store Management option missing in Site Collection
When you navigate to Site Actions –> Site Settings within Site Collection you might notice that under Site Administration section “Term Store Management” option is not available.
A hidden web application feature is probably not activated.
You can activate it through PowerShell or stsadm:
Enable-SPFeature -id “73EF14B1-13A9-416b-A9B5-ECECA2B0604C” -Url <SiteCollection-URL>
Stsadm.exe -o activatefeature -id 73EF14B1-13A9-416b-A9B5-ECECA2B0604C –url http://<SiteCollection-URL> –force