Definition is a rhetorical mode that can be used in something smaller or shorter than a full paper. You can use extended definition for several paragraphs only in a paper of much greater length. You also can add to a paper a one-paragraph definition--like a brief encyclopedia definition.
Immunodeficiency: Therapies include thymus transplantation and adoptive transfer of mature T cells (ATMTC) for individuals with complete DiGeorge syndrome and appropriate prophylaxis measures and monitoring autoimmune complications for incomplete or partial DiGeorge syndrome.
Glial cells in Alzheimer's disease: preferential effect of APOE risk on scattered microglia.Saitoh T(1), Kang D, Mallory M, DeTeresa R, Masliah E. Author information: (1)Department of Neurosciences, University of California-San Diego, La Jolla 92093-0624, USA.lial cells in Alzheimer's disease: preferential effect of APOE risk on scattered microglia.