The term 'Meltrandi' was coined in the 1984 movie Macross: Do You Remember Love, derived from the term 'meltran' meaning female (with zentran meaning male). The original 1982 TV series did not make this distinction, instead referring to both female and male aliens as Zentradi. In a strictly canonical sense it may be best to ignore the Meltrandi term, (though it was also used in Macross 7) though I haven't been watching Macross F and don't know what terms they use there.