build in

to include a feature when something is being put together You should build in some way to cancel the contract if things don't work out. Software developers built in a word processor.

Also, build into. Construct or include as an integral part; also, make automatic, concomitant, or inherent. For example, Frank Lloyd Wright liked to build in as much furniture as possible, not just bookcases but desks, tables, and the like , or We've got to build some slack into the schedule for this project. The literal usage referring to physical objects dates from the late 1920s. The figurative arose a decade or so later. Both are frequently used in past participle form, that is, built in.