# Loop quantum gravity Reference Libraries

String Theory -- A string theory is a physical model whose fundamental building blocks are extended objects (strings, membranes and higher-dimensional objects) rather than points. String theories are able to avoid problems, such as infinite energy density, associated with the presence of mathematical points in a physical theory. The term 'string theory' properly refers to both the 26...

Spacetime -- In special relativity and general relativity, time and three-dimensional space are treated together as a single four-dimensional manifold called spacetime (alternatively, space-time; see below). A point in spacetime may be referred to as an event. Each event has four coordinates (t, x, y, z). Just as the x, y, z coordinates of a point depend on the axes one is using, so...

- Like a worm in form or movement; vermiform; tortuous or sinuous; also, writhing or wriggling.
- Like the track or trace of a worm; appearing as if worm-eaten; vermiculate.
- Marked with fine, close-set, wavy or tortuous lines of color; vermiculated.
- A form of rusticated masonry which is so wrought as to appear thickly indented with worm-tracks.