ɪn lˈɪnɪɹ ˈældʒᵻbɹə, ɐ dᵻfˈɛktɪv mˈeɪtɹɪks ɪz ɐ skwˈɛɹ mˈeɪtɹɪks ðæt dʌznˌɑːt hæv ɐ kəmplˈiːt bˈeɪsɪs ʌv ˈaɪdʒənvˌɛktɚz, ænd ɪz ðˈɛɹfoːɹ nˌɑːt daɪˈæɡənəlˌaɪzəbəl.
In linear algebra, a defective matrix is a square matrix that does not have a complete basis of eigenvectors, and is therefore not diagonalizable.