Как поставить переменную в массив?

Question

[Ibishka]

Как поставить переменную (derevo,malenkiy,mama,brat) в массив?
var derevo = ["д","е","р","е","в","о"];
var malenkiy = ["м","а","л","е","н","ь","к","и","й"];
var mama = ["м","а","м","а"];
var brat = ["б","р","а","т"];