(communication) Initialism of historical data access (an OPC standard)

(algebra) Initialism of higher-dimensional algebra. / (genetics) Initialism of helicase dependent amplification. / (hydrology) Initialism of high-density amorphous ice.

Abbreviation of hot-dip aluminized.

(communication, programming) Initialism of OPC Historical Data Access (group of standards of the OPC Foundation that provides COM specifications for communicating data from devices, like databases, and applications that provide historical data.)