The dictionary is a form dictionary, at least in the sense that complete forms are used as the basis for matching text occurrences with dictionary entries. Also, the dictionary is divided into at least two parts: the list of dictionary forms and the file of information that pertains to these forms. A more detailed description of dictionary operations -- text lookup and dictionary modification -- give a clearer picture.

Text lookup, as we will describe it, consists of three steps. The first is compiling a list of text forms, assigning an information cell to each, and replacing text occurrences with the information cell assigned to the form of each occurrence. For this step the computer memory is separated into three regions: cells in the W region are used for storage of the forms in the text form list; cells in the X-region and Y region are reserved as information cells for text forms.

When an occurrence ** f is isolated during text reading, a random memory address ** f, the address of a cell in the X-region, is computed from the form of ** f. Let ** f denote the form of ** f. If cell ** f has not previously been assigned as the information cell of a form in the text form list, it is now assigned as the information cell of ** f. The form itself is stored in the next available cells of the W-region, beginning in cell ** f. The address ** f and the number of cells required to store the form are written in ** f; the information cell ** f is saved to represent the text occurrence. Text reading continues with the next occurrence.