Being built or under construction, as a structure or a vessel.

present participle of build on

(transitive) To add additional elements or components to (a framework, a concept, a device, etc.) in order to extend it.

(transitive) to add components to a larger entity without interfering with the purpose or functionality of the larger entity

(transitive) to add components to a larger entity without interfering with the purpose or functionality of the larger entity / (transitive) to build something in the interior of an entity

(literally) A component that is part of a larger construction, such as a brick or a stone.

A residential building containing multiple apartments or flats.

plural of building block

(US) A building constructed around a frame of timbers / (US) A similar building in which metal poles are used instead of timbers

(Britain, Australia, banking) A type of financial institution which traditionally was based on lending money (as mortgages) to society members to buy houses, from other members pooled savings and/or money borrowed wholesale.