1.
Michael Fisher asks:
what does DH stand for?
Michael Fisher, New York
2.
The Kollel replies:
It is the initials of "Dibur ha'Maschil", which means literally "the beginning words" or heading. It is the common way of referring to a particular section of a text.
Kollel Iyun Hadaf
3.
M Schwimmer adds:
It's the the equivalent of s.v. used in English, from the Latin 'sub verbo' meaning 'under the word' or 'under the heading'.
Respectfully,
Mordechai Schwimmer