J
justified
Alignment where each line of text is adjusted to exactly fill the column width, resulting in straight margins on both edges (right hand column above). See alignment.
K
kerning
Adjusting the space between adjacent letters in a word.
L
landscape
Format which is wider than it is tall; said of pictures or (more rarely) whole publications.
layout
A design for a page or feature.
leading
Line spacing, measured in points. Pronounced 'ledding' not 'leeding'.
leader
(1) a leading article
(2) a row of dots, as between an item title and page number in a contents list (also leader line)
leading article
The column in a newspaper which presents the paper's view on the biggest current story.
lede
(US) a leading article, or the start of any article.
loose inserts
Advertising leaflets inserted into a publication after binding. Loose inserts are adored by ad sales departments because they generate revenue without taking up any ad pages in the magazine.
literal
Grammatical or spelling error.
litho, lithography
Printing process used for magazines.
M
masthead
(1) The magazine logo.
(2) A more formal name for a flannel panel.
measure
The line length of a piece of text. Long measures are harder to read, and generally need more to be legible.
N
nutgraph
(US) A paragraph (or graph) near the top of a news story explaining why the story is important.
O
OBC
Outside back cover.
OFC
Outside front cover.
orphan
A single line of a paragraph at the top or bottom of a column.
overmatter
Copy for which there is no space available in the layout.