Contraction: The generic term for a braille sign that represents a group of letters or a whole word.
Contractions can occupy one or more cells.
Groupsign: A contraction that represents a group of letters within a word.
Wordsign: A contraction that represents a whole word.
Shortform: A contraction where a word has been specially abbreviated in braille.
Upper sign: A sign that contains a dot 1 or a dot 4.
Lower sign: A sign that contains neither dot 1 nor 4.
Strong sign: A sign that has dots in the top AND bottom rows, PLUS dots in the left AND right sides of the cell.