Entry 2 senses · 2 variants Webster, 1913 Overstock /ōv'-ẽrs-täk'/ · O·ver·stock · IPA /ˈoʊvərstˈɑk/ n. v. t. 01 n. Stock in excess. 1. Stock in excess. 02 v. t. To fill too full; to supply in excess; as, to overstock a market with goods, or a farm with cattle. imp. & p. p. Overstocked; p. pr. & vb. n. Overstocking 1. To fill too full; to supply in excess; as, to overstock a market with goods, or a farm with cattle.