Smith’s Bible Dictionary
“Michtam” means golden psalm
Michtam: This word occurs in the titles of six psalms (16,56-60), all of which are ascribed to David. The marginal reading of our Authorized Version is "a golden psalm," while in the Geneva version it is described as "a certain tune." From the position which it occupies in the title we may infer that michtam is a term applied to these psalms to denote their musical character, but beyond this everything is obscure.