Initialism of his apostolic majesty, the title given to a number of historical kings of Hungary.

(computer graphics) Initialism of Hold-And-Modify, a display mode of the Commodore Amiga computer, allowing for a large number of colours on screen.

(chiefly African-American Vernacular) Initialism of hard as a motherfucker, extremely hard, extremely intensely, crazily.

plural of Ham

Place-name suffix, variously indicating a settlement, farm or enclosure.

present participle of ham up

plural of Hamming code

(information theory) Given two strings of equal length, the number of positions at which the corresponding symbols differ; it therefore indicates the minimum number of substitutions required to change one string into the other.

plural of Hamming distance

(telecommunications) Any of a family of linear error-correcting codes that generalize the Hamming(7,4)-code invented by Richard Hamming in 1950.