It's kinda like no strict 'vars';, but it only applies to a single variable.
It means "yes, a package variable with that name exists, so don't complain about it."
Thats a common but incomplete interpretation. "our" works also useful without "strict", so it's not about complaining or not.
And there are important differences to no strict 'vars', because the chosen namespace can be very different from what you expect: With our it's the stash of the package at declaration position, like with my where it's the lexpad at declaration position.
But with no strict 'vars' a "non-explicit" variable belongs to the actual package at the encounter position!
UPDATE: So one can't simply refactor a code be replacing
no strict 'vars' with a lot of
ours for each variablename. You have to take care about the local packages!