Cost  —v. (past and past part. Cost) 1 be obtainable for (a sum of money); have as a price. 2 involve as a loss or sacrifice (it cost him his life). 3 (past and past part. Costed) fix or estimate the cost of. —n. 1 what a thing costs; price. 2 loss or sacrifice. 3 (in pl.) Legal expenses.  at all costs (or at any cost) whatever the cost or risk may be. [latin consto stand at a price]