Dalek army
The "Dalek army" referred to the gathered forces of the Dalek race, (TV: Resurrection of the Daleks) typically when discussing their ground forces. (TV: Planet of the Daleks, et. al) However, the ability for Daleks to operate in atmospheres (TV: The Stolen Earth) and space through flight meant a "Dalek army" could do more than simply attack on ground. (TV: The Parting of the Ways) The Dalek army could thus besiege and attack locations in space, in atmospheres, and on ground, (TV: The Parting of the Ways, The Stolen Earth) attacking targets by flying above or landing on the ground. (TV: Doomsday)
During a Dalek invasion, the Dalek army would work alongside the Dalek Fleet, with Daleks operating in the fleet easily joining the "army" unit if the attack called for it. (TV: The Parting of the Ways, Revolution of the Daleks) Being a warrior race totally focused on conquest and extermination, (TV: The Witch's Familiar, et. al) every individual Dalek was part of the overall Dalek army, even if that specific Dalek was currently operating aboard a warship of the Dalek Fleet branch. (TV: Resurrection of the Daleks)
Structure
Formation
The overall army branch was divided into individual armies of Daleks, (TV: Planet of the Daleks, et. al) which could be further split into units as small as squads or large units, including battalions, (PROSE: Birth of a Legend) legions, (PROSE: The Third Wise Man) and divisions also existed under the overall (PROSE: Dalek Survival Guide)
Tactics
For Dalek invasions, Dalek saucers or other such ships would attack from above, while Dalek ground forces would attack on the ground or while flying themselves. (TV: The Last Day, The Day of the Doctor, et. al)
History
The Dalek Empire named its overall army branch the Imperial Dalek Army. (COMIC: Emperor of the Daleks!) The New Dalek Paradigm and Resurrected Dalek Empire called their overall army the Dalek Imperial Army. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)
