
1) Army unit 2) Providing strict order 3) Type of flag or colors
Found on
https://www.crosswordclues.com/clue/regimental

• (a.) Belonging to, or concerning, a regiment; as, regimental officers, clothing.
Found on
http://thinkexist.com/dictionary/meaning/regimental/
Reg`i·men'tal adjective Belonging to, or concerning, a regiment; as,
regimental officers, clothing.
Regimental school ,
in the British army, a school for the instruction of the private soldiers of a regiment, and their children, in the rudimentary branches of education. Found on
http://www.encyclo.co.uk/webster/R/39

Regimental is British army slang for downfall.
Found on
http://www.probertencyclopaedia.com/browse/ZR.HTM

[
adj] - belonging to or concerning a regiment
Found on
http://www.webdictionary.co.uk/definition.php?query=regimental
adjective belonging to or concerning a regiment; `regimental units`
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.