Zekkie was an affectionate nickname given to Grand Nagus Zek by Ishka. (DS9: "Profit and Lace", "The Dogs of War")
When Quark first caught Zek and Ishka (his "Moogie") together at her home in 2373, she called out for "Zekkie!", leaving Quark to repeat, "Zekkie?", in disbelief. (DS9: "Ferengi Love Songs")