Terms and Defintions

Grid, simply defined is:

A framework of crisscrossed or parallel bars; a grating or mesh.

A cooking surface of parallel metal bars; a gridiron. (not what we're really going for)

A pattern of regularly spaced horizontal and vertical lines forming squares on a map, a chart, an aerial photograph, or an optical device, used as a reference for locating points.

A modular grid looks something like

It has consistent horizontal and vertical divisions from top to bottom and left to right, respectively, which govern the placement and cropping of text and pictures

DESIGNERS use modular grids for control and structure. By using modular grids, designers are able to arrange and manipulate text and images in many different ways within the structure of the grid, experimenting with the alignment of text and images and various texts and font sizes, in an easy and structured manner

The margins are the areas around the workable area of a grid; the outside boundary. This area is to be left uncovered.
Columns are vertical blocks in a layout which are separated between margins.
Grid modules are the primary locations on your page where you will place text and images. They determine placement not necessarily size.
Flowlines are the lines in between characters
The gutter is the space between each module, including the space found in the fold of a book.

Hierarchy: is a way to express the relative importance of different text elements, images, or both by providing a visual guide to their organization; what the viewer should see 1st, 2nd and 3rd. A text hierarchy helps make a layout clear and easy to understand.To achieve clear hierarchy a designers should take into consideration placement, weight on type style, the size and scale, and the use of graphic elements.
A type family contains typefaces that have condensed and extended versions of display faces, commonly seen as distinct but related.
Type styles include the full set of standardized letter forms designed for reproduction through print.