| Noun | 1. | building block - a single undivided natural thing occurring in the composition of something else; "units of nucleic acids"thing - a separate and self-contained entity chemical chain, chain - (chemistry) a series of linked atoms (generally in an organic molecule) couple - (physics) something joined by two equal and opposite forces that act along parallel lines part, piece - a portion of a natural object; "they analyzed the river into three parts"; "he needed a piece of granite" unit cell - the smallest group of atoms or molecules whose repetition at regular intervals in three dimensions produces the lattices of a crystal chemical group, radical, group - (chemistry) two or more atoms bound together as a single unit and forming part of a molecule molecule - (physics and chemistry) the simplest structural unit of an element or compound |
| 2. | building block - a block of material used in construction work ashlar - a rectangular block of hewn stone used for building purposes breeze block, cinder block, clinker block - a light concrete building block made with cinder aggregate; "cinder blocks are called breeze blocks in Britain" voussoir - wedge-shaped stone building block used in constructing an arch or vault building material - material used for constructing buildings |