thinning Smith-Hall thinning (subs.): of vines, extenuatio, Plin. 17, 26, 39: pampinatio, id. 17, 1, 1: more gen., of trees, etc., interlucatio, id. 17, 27, 45: attenuatio (used fig. in Cic.) is used in M. L. for the t. of a fluid: v. DILUTION.