Why DIP stands for Dual In-line Package, and the name describes the physical layout: the plastic or ceramic body has two parallel rows of pins running down opposite long sides, spaced 0.1 inch apart, meant to be inserted through holes in a circuit board or into a socket. The word 'dual' refers to the two rows of leads, not to anything electrical inside the chip. DIPs are through-hole parts, in contrast to surface-mount packages like SOIC, SOT and leadless chip carriers that are preferred at VHF and above because of their shorter leads.
Watch out The choice about two chips in one package misreads 'dual' as counting dies; a DIP normally holds a single die, and the lead inductance of those long pins actually makes DIPs worse, not better, for stray reactance at RF.
DIP = Dual In-line Package: two in-line rows of pins, one down each side.