Gifted individuals are those who demonstrate outstanding levels of aptitude (defined as an exceptional ability to reason and learn) or competence (documented performance or achievement in top 10% or rarer) in one or more domains. Domains include any structured area of activity with its own symbol system (e.g., mathematics, music, language) and/or set of sensormotor skills (e.g. painting, dance, sports).
—National Association for Gifted Children (NAGC)
Giftedness is asynchronous development in which advanced cognitive abilities and heightened intensity combine to create inner experiences and awareness that are qualitatively different from the norm. This asynchrony increases with higher intellectual capacity. The uniqueness of the gifted renders them particularly vulnerable and requires modifications in parenting, teaching and counseling in order for them to develop optimally.
—The Columbus Group, 1991. Cited by Martha Morelock, "Giftedness: The view from within,” in Understanding Our Gifted, January 1992
Twice-exceptional (2E) refers to children who are identified as gifted and talented in one or more areas of exceptionality (specific academics, general intellectual ability, creativity, leadership, or performing arts). Twice-exceptional also refers to children who are identified with another exceptionality defined by Federal or State eligibility criteria (reading, math, written expression, and/or speech/language disorders, emotional/behavioral disorders, physical disabilities, Autism Spectrum Disorders, or other health impairments such as ADHD).
—An Operational Definition of Twice-Exceptional Learners: Implications and Applications by Sally M. Reis, Susan M. Baum, and Edith Burker in Gifted Child Quarterly, June 2014