Major constituent groups of Assamese / Asamiya people
The Assamese people(অসমীয়া জাতি) are a subgroup of the people of Assam(অসমৰ জনগোষ্ঠী). The Assamese people make up the majority of Assam's population. The population of Assamese people in Assam is 13,000,000 making up 45.00 % of Assam population at 2011 census. This subgroup is often associated with the Assamese language(অসমীয়া ভাষা) Historically, the definition of the "Assamese people" has remained in flux and this has had strong political repercussions in Assam, especially in the colonial (1826–1947) and post-colonial (after 1947) periods.
The lack of a definition has put stumbling blocks in implementing clause 6 of the Assam Accord(অসম চুক্তি), an agreement signed by the activists of the Assam Movement(অসম আন্দোলন) and the Government of India in 1985. Since a legal definition is important to provide "constitutional, legislative and cultural" safeguards to the Assamese people, the Government of Assam(অসম চৰকাৰ) had formed a ministerial committee to finalize the definition in March 2007. To address the clause 6 issue AASU(সদৌ অসম ছাত্ৰ সন্থা) had announced a definition on April 10, 2000 which was based on residency with a temporal limit: "All those whose names appeared in the 1951 National Register of Citizens and their progenies should be considered as Assamese". Difficulty in definition is rooted in the heterogeneous nature of inhabitants of the Assam state.
In contrast, Western Assam in pre-colonial times was known as "Kamrup" (কামৰূপ) (instead of Asama, and considered a politically, socially and culturally separate unit from the rest of the state.
In the 16th-century, the Ahom kingdom(আহোম ৰাজ্য) came to be known as the "Kingdom of Acham" to the Mughals; and following them, the British. In 1682 the eastern Kamrup was annexed by Ahom kingdom and the expanded kingdom continued to be called "Kingdom of Assam" till 1821 when the Ahom kingdom became part of the Burmese Empire.
Just as "Assam" was associated with the Ahom kingdom till the 19th century "Asamiya" was used for the subjects and soldiers of that kingdom who belonged to different ethnic and linguistic backgrounds and not solely to the Ahom community.[not in citation given]
After Assam became part of British India, the newly constituted province came to be known as Assam after its largest constituent, and the name Assamese / Asamiya(অসমীয়া) came to be associated with the Assamese language erstwhile known as Kamrupi(কামৰূপী). 
According to Yasmin Saikia, "the group that now identifies as Tai-Ahom were historically seen as Assamese people. However, the term ethnic Assamese is now associated by the Indian government at Delhi with the Assamese speaking Indo-Aryan(ইণ্ডো-আৰ্য) group (comprising both Hindus and Muslims) of Assam. The latter group is the majority people of Assam, while the Tai-Ahom people were a dominant minority during the Ahom Rule".
^Clause 6 of Assam Accord: "Constitutional, legislative and administrative safeguards, as may be appropriate, shall be provided to protect, preserve and promote the cultural, social and linguistic identity and heritage of the Assamese people."
^Sukalpa Bhattacharjee, C Joshua Thomas,2013,Society,Representation and Textuality:The Critical Interface It deals with the expansion of the Mughal Empire in Bengal, Kamrup and Assam.
^Satish Chandra (2005), Medieval India:Fro Sultanate to the Mughals Part - II They had support of many Hindu Rajas of Jessore, Kamrup (Western Assam), Cachar, Tippera, etc.
^Peter Jackson,2003,The Delhi Sultanate: A Political and Military History,P. 141, "No body sought to emulate Mohammad b. Bakhtiar, who had returned a broken man from a disastrous campaign through the Upper Brahmaputra region, possibly into the region of Assam the Muslims called Kamrup or Kamrud
^Goswami, Upendranath (1970), A Study on Kāmrūpī: A Dialect of Assamese, Page iii
^Bowrey, Thomas (1663) A Geographical Account of Countries around Bay of Bengal, ed Temple, R. C., Hakluyt Society's Publications. In this account, Bowrey describes the death of Mir Jumla, who had occupied the capital of the Ahom kingdom in the 17th century thus: "They lost the best of Nabobs, the Kingdome of Acham, and, by consequence, many large privileges".
^"In the Battle of Itakhuli in September 1682, the Ahom forces chased the defeated Mughals nearly one hundred kilometers back to the Manas river. The Manas then became the Ahom-Mughal boundary until the British occupation." (Richards 1995, p. 247)
^"The Kingdom of Assam, where it is entered from Bengal, commences on the north of the Berhampooter, at the Khonder Chokey, nearly opposite to the picturesque estate of the late Mr Raush at Goalpara; and at the Nagrabaree Hill on the South", Wade, Dr John Peter, (1805) "A Geographical Sketch of Assam" in Asiatic Annual Register, reprinted (Sharma 1972, p. 341)
^Baruah, S. L. (1993), Last Days of Ahom Monarchy, P.225
^"The Ahoms were never numerically dominant in the state they built and, at the time of 1872 and 1881 Censuses, they formed hardly one-tenth of the populations relevant to the erstwhile Ahom territory (i.e, by and large, the Brahmaputra Valley without the Goalpara district.)" (Guha 1983:9)
^Sukumar Sen, Grammatical sketches_of Indian languages_with comparative_vocabulary and texts, P31