What was called Rajputana by the British.

Hint: The name Rajputana means " land of Rajputs" this consisted of two geographic divisions: the area northwest of the Aravalli Range, this being mostly sandy and unproductive and including part of the Great Indian (Thar) Desert; and the area southeast of the range, which is generally higher and more fertile.

Complete answer: In the $19^{th}$ century, the region that constitutes most of the present-day Rajasthan was called Rajputana by the British, it was also called Rajwar, which was a former group of princely states. This area was known as Rajputana around the time when Kachwaha, a Rajput clan, migrated to the region. The Kachwa has continued to assist their Rajput allies in many Fatal battles including First Battle of Tarain and later in the disastrous Second Battle of Tarain. The last time where Kachwahas fought for Rajputs was under Rana Sanga of Chittor in the Battle of Khanwa.

After the defeat, the Kachwahas accepted the Supremacy of Mughals under the Akbar reign.
The region was previously long known as Gujratra (an early form of "Gujarat"), before it came to be called Rajputana during the medieval period

Note: The early medieval period saw the rise of many Rajput kingdoms like Chauhans of Ajmer, Guhilot and Sisodias of Mewar, Rathores of Marwar. Later the region came under the suzerainty of the Mughal Empire. The Mughals granted high positions to Rajput rulers who allied with them. However, some Rajput kingdoms did not accept Mughal suzerainty and were constantly at war with them. The Mughal rule effectively ended in the 18th century, in Rajasthan and Maratha influence grew in the region.