Hardening.
Locked-down version of Linux = Hardened Linux
Lock-down version of Tomcat: Tomcat hardening
Ringlet
No it isnt. it has four words
Tress and strand are the ones I can think of at THISmoment.
Its just another word for lock key Xx
calm down
Lock keeper is the word you are looking for.
Scroll lock might be turned on
insult
oscillation
descend
abdicate
decreasing