Definify.com
Webster 1913 Edition
Subsesqui-
Sub-ses′qui-
.[Pref.
sub-
+ sesqui-
.] (Chem.)
A prefix (also used adjectively) denoting the combination of constituents (especially electro-negative and electro-positive bodies) in the proportion of two to three;
as, a
subsesqui
acetate, i. e., a salt having two equivalents of acetic acid to three of the base.