off-diagonaladj.n.
/ˌɒfdʌɪˈaɡ(ə)nl/, /ˌɒfdʌɪˈaɡn̩l/, U.S. /ˌɔfdaɪˈæɡən(ə)l/, /ˌɑfdaɪˈæɡən(ə)l/, /ˌɔfdaɪˈæɡn(ə)l/, /ˌɑfdaɪˈæɡn(ə)l/ Mathematics.
Designating an element of a square matrix that is not on the principal diagonal (running from top left to bottom right). Also as n.: an off-diagonal element.
ΘΚΠ
the world > relative properties > number > mathematical number or quantity > numerical arrangement > [noun] > array > matrix > element or quality of
column1846
skew-symmetry1927
entry1928
off-diagonal1932
similarity class1952
the world > relative properties > number > mathematical number or quantity > numerical arrangement > [adjective] > of array > relating to matrices > applied to element
off-diagonal1932
1932 Proc. Royal Soc. A. 136 599 Then the off diagonal components are of a similar order of intensity to the main diagonal lines.
1959 Proc. National Acad. Sci. U.S.A. 45 987 The elements djk in the quadratic form are identified as..[formulae] where djj's are diagonal elements and djk's are off-diagonals.
1972 Jrnl. Social Psychol. 86 198 All possible comparisons are set out here—i.e., including the congruences in the off-diagonals.
1981 A. D. Pierce Acoustics x. 510 The off-diagonal elements are the shear stresses.
1998 N. Maxwell Comprehensibility of Universe 264 The transpose of a matrix..is formed by exchanging off-diagonal elements with each other symmetrically.
This entry has been updated (OED Third Edition, March 2004; most recently modified version published online March 2022).
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adj.n.1932