latent vs masked defects
It is an existing defect in the system which
does not cause any failure as the exact set of
conditions has never been met
Basically when one defect hides other defect
we call it fault masking for example:
If the "Negative Value" cause a firing of unhandled
system exception, the developer will prevent
the negative values input.
This will resolve the issue and hide the
defect of unhandled exception firing.