Prefixes:
* Out-: (to extend beyond) - outline
* Under-: (below) - underline
* Over-: (above) - overline
* Sub-: (under, below) - subline
* Cross-: (going across) - cross-line
* Side-: (at the side) - sideline
* Head-: (at the beginning) - headline
* Base-: (at the bottom) - baseline
* Mid-: (in the middle) - midline
* Inter-: (between) - interline
* Straight-: (without curves) - straightline
* Parallel-: (running side-by-side) - parallelline
* Diagonal-: (slanting) - diagonalline
Suffixes:
* -er: (one who does something) - liner (someone who draws lines)
* -ing: (action or process) - lining (the process of drawing lines)
* -ment: (act or result) - alignment (the act of aligning)
* -ation: (process or action) - linearization (the act of making something linear)
* -al: (relating to) - linear (relating to a line)
Combinations:
You can also combine prefixes and suffixes to create new words:
* Outlining (the act of drawing an outline)
* Underlining (the act of drawing a line under something)
* Sublinear (below the standard linear rate)
* Cross-lining (drawing lines that cross each other)
Remember that not all combinations will create valid words, but these examples illustrate the possibilities!