Subsesqui-
Pronunciation : Sub*ses"qui-.
Etymology : [Pref. sub- + sesqui-.] (Chem.)
Definition : Defn: 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.
Source : Webster's Unabridged Dictionary, 1913