BRITT:OMN meant "of all the Britains", i.e. Queen of all the Britains. It was supposed to be praise for the Dominions who helped Britain during the Boer War. However, it was later thought to be rather patronising and imperialist, so it was dropped.
While I have never quite understood why "Britanniarum" would be abbreviated "Britt" (where does that second T come from?), I liked the idea that the coins would this way have some kind of country indicator: BRITT or BR without any other territorial reference = UK.

Romanian coins roughly between 1950 and 1990 have interesting inscription changes too: The first name of the republic was
Republica Populara Romana, the (1955-60) the last word was changed to
Romina. In 1963 good old
Romana was used again, but in 1965/66 the name changed to
Republica Socialista Romania. All these modifications did not really affect the other design elements ...
Christian