HAD

Hole Accumulated Diode. A type of CCD sensor with a layer designed to accumulate holes (in the electronic sense), thus reducing noise level.
Found on http://www.zoo.co.uk/~z0001325/Glossary.html

Had

Had (hăd) imperfect & past participle of Have . [ Middle English had , hafde , hefde , Anglo-Saxon hæfde .] See Have . Had as lief , Had rather , Had better , Had as soon , etc., with a nominative and followed by...
Found on http://www.encyclo.co.uk/webster/H/2

Had

• (imp. & p. p.) See Have. • (imp. & p. p.) of Have
Found on http://thinkexist.com/dictionary/meaning/had/

Had

HAD was an Australian two-stage solid-propellant sounding rocket of the 1960's that was developed primarily for use in upper-atmosphere measurements. HAD was 594 cm long and carried a payload of up to 9 kg to a height of 129 km at a speed of 5045 kmh.
Found on http://www.probertencyclopaedia.com/browse/IH.HTM

HAD

[Naval Acronyms and Slang] Home Aircraft Depot (RAF)
Found on http://www.encyclo.co.uk/local/21733

HAD

HIV-associated dementia
Found on http://www.translationdirectory.com/glossaries/glossary124.htm
No exact match found