submatrix
[ suhb-mey-triks, -ma-triks ]
/ sʌbˈmeɪ trɪks, -ˈmæ trɪks /
noun, plural sub·ma·tri·ces [suhb-mey-tri-seez, -ma-tri-seez] /sʌbˈmeɪ trɪˌsiz, -ˈmæ trɪˌsiz/, sub·ma·trix·es. Mathematics.
a set of certain rows and columns of a given matrix.