The crossword is the most common variety of word puzzle in the world. Modern crosswords normally take the form of a square grid of black and white squares; the aim is to fill the white squares with letters, forming words (or word phrases) reading across and down, by solving clues which yield the words. The black squares are used to separate words. Squares in which answers begin are usually numbered; the clues are then referred to by these numbers and a direction ? for example, "1-Across" or "17-Down"; at the end of the clue the total number of letters is sometimes given for the convenience of the solver, dependent on the style of puzzle and country of publication.



Terminology

The creating of crosswords is called 'cruciverbalism' among its practitioners, who are likewise referred to as 'cruciverbalists'; the terms derive from the Latin for 'cross' and 'word'. Although the terms have existed for over a decade, non-cruciverbalists rarely use them, calling crossword creators simply 'constructors' or 'setters'.

The horizontal and vertical lines of white cells into which answers are written are commonly called 'entries' or simply 'answers'; the clues themselves are usually called just that, or sometimes 'definitions'. The black and white cells themselves have several terms, such as "darks and lights", "blanks" (which refers to the black cells, which are left unfilled by solvers and serve as spacers), and the like.

A white cell that is part of only one entry - Across or Down, but not both - is usually called 'unchecked'; 'unkeyed' or just 'uncrossed' are other names for this.

Types of grid

Crossword grids such as those appearing in most North American newspapers and magazines feature solid chunks of white squares. Every letter is checked (that is, it is part of an answer reading across and another reading down), and usually each answer is required to contain at least three letters. In such puzzles black squares, used to separate answers, are traditionally limited to about one-sixth of the design. Crossword grids elsewhere, such as in Britain and Australia, have a lattice-like structure, with a higher percentage of black squares, leaving up to half the letters in an answer unchecked. In these puzzles it is normally the case that no two across or down answers may run side-by-side. For example, if the top row has an answer running all the way across, there will be no across answers in the second row.

Another tradition in puzzle design (in North America and Britain particularly) is that the grid should have 180-degree rotational symmetry, so that its pattern appears the same if the paper is turned upside down. Puzzles are often one of several standard sizes. For example, many weekday puzzles (such as the New York Times crossword) are 15'15 squares, while weekend puzzles may be 21'21, 23'23 or 25'25.

The design of Japanese crossword grids often follows three additional rules: that black cells may not share a side, that all white cells must be orthogonally contiguous (that is, connected in one mass through shared sides, or form a single polyomino), and that the corner squares must be white.

Substantial variants from the usual forms exist. Two of the common ones are barred crosswords which use bold lines between squares (instead of black squares) to separate answers, and circular designs, with answers to be entered either radially or in concentric circles. Free form crosswords have simple designs and are not symmetric.

Typically, clues appear outside the grid, divided into an Across list and a Down list; correspondingly, the first cell of each entry contains a number referenced by the clue lists - for example, the answer to a clue labeled "17-Down" would be entered with the first letter in the cell numbered '17' and proceed down from there. Numbers are almost always never repeated; instead, all cells that require clue numbers are labeled consecutively, usually from left to right across each row, starting with the top row and proceeding downward (some Japanese crosswords are numbered from top to bottom down each column, starting with the leftmost column and proceeding right).

German and Brazilian crosswords usually don't number the clues; instead, the clues themselves are found in small print inside the grid cells, each clue with a little arrow indicating in which direction from its cell the answer is to be written. These "clue boxes" are usually the only (or nearly so) "black squares" in such puzzles. This is not uncommon in other languages as well (English examples are regularly published in GAMES Magazine under the title Pencil Pointers).

Answers are printed in upper case letters. This ensures a proper name can have its initial capital letter checked with a non-capitalizable letter in the intersecting clue. Diacritical markings in foreign loanwords are ignored for similar reasons. This also applies in foreign-language puzzles; for example, in French, the initial ? of answer ?TRE can double as the final ? of CONG? when written ETRE and CONGE. In German language crosswords, the umlauts '?', '?', and '?' are dissolved into 'ae', 'oe', and 'ue', and ? is dissolved into ss.

Types of clues

Straight or quick

In some crosswords, often called straight or quick, the clues are usually simple definitions for the answers. Some clues may feature anagrams, but these are usually explicitly described as such. Often, a straight clue is not in itself sufficient to distinguish among several possible answers (often synonyms), and the solver must make use of checks to establish the correct answer with certainty. A key point to remember when solving crosswords is that crossword answers and their clues always agree in tense and number. If a clue is in the past tense, then so is the answer: "Traveled on horseback" = RODE, but never RIDE. Similarly, "Family members" would be a valid clue for AUNTS but not UNCLE (since the latter is singular while the clue is plural). Some clue examples:

Fill-in-the-blank clues are often the easiest in a given puzzle, and a good place to start solving. Ex.: "__ Boleyn" = ANNE

Abbreviations, use of foreign language, variant spellings, or other unusual word tricks are indicated in the clue. A crossword creator might choose to clue the answer SEN (as in the abbreviation for "Senator") as "Washington bigwig: Abbr." or "Member of Cong.", with the abbreviation in the clue indicating that the answer is to be similarly abbreviated. The use of "Var." indicates the answer is a variant spelling (e.g., EMEER instead of EMIR), while the use of foreign language or a foreign place name within the clue indicates that the answer is also in a foreign language. For example, ETE (French for "summer") might be clued as "Summer, in the Sorbonne" while ROMA could be clued as "Italia's capital."

A question mark at the end of clue usually signals that the clue/answer combination involves some sort of pun. Ex.: "Grateful?" = ASHES (since a grate might be full of them).

The clue "PC key" for a three-letter answer could be ESC, ALT, TAB, or even DEL, but until a check is filled in, giving at least one of the letters, the correct answer cannot be determined.

A common clue is "Compass point", where the desired answer is one of eight possible abbreviations for a position on a compass, i.e. NNW (for north-northwest) or ESE (for east-southeast). The desired answer is determined by a combination of logic - since the third letter can be only E or W, and the second letter can be only N or S - and a process of elimination using checks. Alternatively, compass point answers are often clued as "XXX to YYY direction", where XXX and YYY are two place names. For example, SSW might be clued as "New York to Washington direction".

Most widely distributed American crosswords today (e.g., The New York Times, Washington Post, Boston Globe, USA Today, etc.) also contain "speech"-like answers, i.e., entries in the puzzle grid that try to replicate our everyday colloquial language. In such a puzzle, one might see phrases such as WHAT'S UP, AS IF, or WHADDYA WANT.