Does aneuploidy include the loss of chromosome arms?
To my knowledge aneuploidy regards to chromosome numerical change, not to losses within chromosomes.
Take a look at this paragraph from An Introduction to Genetic Analysis. 7th edition (Griffiths AJF, Miller JH, Suzuki DT, et al. New York: W. H. Freeman; 2000.)


  Aneuploidy is the second major category of chromosome mutations in
  which chromosome number is abnormal. An aneuploid is an individual
  organism whose chromosome number differs from the wild type by part of
  a chromosome set. Generally, the aneuploid chromosome set differs from
  wild type by only one or a small number of chromosomes. Aneuploids can
  have a chromosome number either greater or smaller than that of the
  wild type. Aneuploid nomenclature is based on the number of copies of
  the specific chromosome in the aneuploid state. For example, the
  aneuploid condition 2n − 1 is called monosomic (meaning “one
  chromosome”) because only one copy of some specific chromosome is
  present instead of the usual two found in its diploid progenitor. The
  aneuploid 2n + 1 is called trisomic,2n − 2 is nullisomic, and n + 1 is
  disomic.


This term (aneuploidy) was coined by Gunnar Täckholm in 1922, and if you want to check the original description you can just look for his original paper:

Täckholm, G. Zytologische Studien über die Gattung Rosa. Acta Hort. Berg. 7, 97–381 (in German) (1922).