subframe

noun

1. A subsidiary frame (chunk of data).

   “Four status bits accompany each subframe.”

2. A structural component of a vehicle, such as an automobile or aircraft, that uses a discrete, separate structure within a larger body-on-frame or unit body to carry certain components, such as the engine, drivetrain, or suspension.

   “In the rebuilding no alterations have been made to the queen-post underframes except to add the subframe carrying the engine-transmission group.”

3. (Internet)One of the HTML frames that make up a frameset.

   “Specify the dimensions of your main frame and subframes and this online utility will create them for you.”