1. To shift the contents of a register or a field so that the significant character at the specified end of the data is at a particular position.
2. To align text horizontally or vertically so that the first and last characters of every line, or the first and last line of the text, are aligned with their corresponding margins.
Note 1: In English, text may be justified left, right, or both. Left justification is the most common.
Note 2: The last line of a paragraph is usually only left justified.
3. To align data on a designated character position.
Source: from Federal Standard 1037C