sd

noun

1. 1.(law enforcement) Initialism of sheriff's department.
2. 2.Initialism of self-destruct.
3. 3.A governmental district that operates local public primary and secondary schools.
4. 4.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).
5. 5.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.