subbase for a topology

subbase for a topology

[′səb‚bās fȯr ə tə′päl·ə·jē]
(mathematics)
A family S of subsets of a topological space X where by taking all finite intersections of sets from S and all unions of such intersections the entire topology of open sets of X is obtained.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.