- Checking
- When a letter appears in both an Across and a Down answer. In American-style crosswords, every letter is fully checked (part of two words). In British-style, some letters may be unchecked.
- Clue
- The hint or definition provided for each answer. Clues can be straightforward definitions, wordplay, fill-in-the-blank, or cryptic constructions.
- Constructor
- The person who creates a crossword puzzle. Also called a setter (British) or cruciverbalist.
- Cross
- The intersection point where an Across answer and a Down answer share a letter. Crosses provide hints for both words.
- Crosswordese
- Common short words that appear frequently in crosswords due to their useful letter combinations. Examples: ERA, ORE, ARIA, ALOE, EPEE, OREO, OLEO, ANTE, ERNE.
- Cryptic clue
- A clue style used primarily in British crosswords where each clue contains both a definition and wordplay (anagram, hidden word, reversal, etc.) leading to the same answer.