(law enforcement) Initialism of sheriff's department.
Initialism of self-destruct.
A governmental district that operates local public primary and secondary schools.
A system that uses a resolution that is not considered to be either high-definition television (720p, 1080i, 1080p, 1440p, 4K UHDTV, and 8K UHD) or enhanced-definition television (EDTV 480p).
A measure of how spread out data values are around the mean, defined as the square root of the variance. Represented with the Greek letter σ.