Why TSR can mean different things in different services

Doesn't TSR mean tactical strike reconnaissance rather than torpedo-spotter-reconnaissance?

Both meanings occur: the Royal Navy used torpedo-spotter-reconnaissance in the Swordfish context, while the later RAF designation meant tactical strike reconnaissance.

TSR meant torpedo-spotter-reconnaissance in the Royal Navy context of the Swordfish. The later RAF usage was tactical strike reconnaissance, reflected in TSR-2. The armed forces reused the same initials for different requirements, and services did not always agree on what the letters meant. A designation therefore needs to be read against the service and period that used it.