From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Hammedatha (  Esther 3:1;   Esther 3:10;   Esther 8:5;   Esther 9:10;   Esther 9:24; in Ad. Est 12:6, 16:10, 17 Amadathus ). The father of Haman. The name is probably Persian; possibly the etymology is mâh = ‘moon’ data = ‘given.’

Smith's Bible Dictionary [2]

Hammed'atha. (Double). Father of the infamous Haman.  Esther 3:1;  Esther 3:10;  Esther 8:5;  Esther 9:24.

Fausset's Bible Dictionary [3]

Haman's father. Medatha with the definite article, Ha- . (See Esther ; Haman In Persian, it means "double".

Easton's Bible Dictionary [4]

 Esther 3:1,10 8:5

Morrish Bible Dictionary [5]

An Agagite, father of Haman.  Esther 3:1,10 , etc.

Holman Bible Dictionary [6]

 Esther 3:1

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [7]

(Heb. Hammedatha', הִמְּדָתָא ; Sept. Ἀμάδαθος , Vulg. Amadathus, but both sometimes omit), father of the infamous Haman (q.v.), and commonly designated as "the Agagite" ( Esther 3:1;  Esther 3:10;  Esther 8:5;  Esther 9:24), though also without that title (9, 10). By Gesenius (Lex. 1855, p. 539) the name is taken to be Medatha, preceded by the definite article; but Furst (Lex. s.v.), with more probability, identifies it with the Zendic hamodata, i.e "given by Hom," one of the Izeds. For other explanations, see Simonis (Onomasticon, p. 586), who derives it from a Persian word meaning "double." For the termination, compare (See Aridatha). B.C. ante 474.

International Standard Bible Encyclopedia [8]

ham ē̇ dā´tha המּדתא hammedhāthā'   Esther 3:1