**Anagram**- a word or phrase formed by transposing the letters of another. For example:
**PRIEST** - **STRIPE**.

**Bidirectional word**- a word which can be read in two directions: from the left to the right and from the right to the left. For example:
**REDRAW** - **WARDER**.

**Cryptorithm**- a mathematical puzzle involving words where there is a one-to-one mapping between letters and digits that makes the arithmetic equation true.
For example:
**MOTHER+FATHER=PARENT** => **196753+286753=483506**

**Isogram**- a word or phrase in which each letter occurs the same number of times. For example:
**RAPPAREE** (each letter twice).

**Latin square**- a square matrix of order
*N* in which each row and each column are permutations of the elements of a finite set *S* consisting of *N* elements.

**Nonogram file**- a file with the numbers which describe the puzzle (numbers to the left of the rows and on the top of the columns).

**Nonogram solution file**- a file with the picture corresponding to the numbers to the left of the rows and on the top of the columns.

**Pattern**- a series of known letters in known positions with wildcard characters in the positions where the letters are not known.

**Reverse dictionary**- a list of words sorted by their last letters.

**Word "weight"**- a sum of letter numbers in the alphabet. For example, the "weight" of the word
*abbey*: **1+2+2+5+25 = 35**.